CN107253983A - A kind of recombinant protein composition for detecting toxoplasma antibody and preparation method thereof - Google Patents

A kind of recombinant protein composition for detecting toxoplasma antibody and preparation method thereof Download PDF

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CN107253983A
CN107253983A CN201710507519.2A CN201710507519A CN107253983A CN 107253983 A CN107253983 A CN 107253983A CN 201710507519 A CN201710507519 A CN 201710507519A CN 107253983 A CN107253983 A CN 107253983A
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mic2
sag1
recombinant protein
amino acid
protein composition
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杨致亭
刘泽军
丁兆明
徐冬梅
张守永
王婷
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WEIFANG HIGHTOP BIOTECH CO Ltd
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    • C12N15/63Introduction of foreign genetic material using vectors; Vectors; Use of hosts therefor; Regulation of expression
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Abstract

The invention belongs to Biological Detection technical field, a kind of recombinant protein composition for detecting toxoplasma antibody is specifically provided, recombinant protein composition is made up of the recombinant protein of SAG1 specific epitopes and the recombinant protein of MIC2 specific epitopes.Present invention also offers the preparation method of recombinant protein.Recombinant protein composition has high specific and high sensitivity in the present invention, uses it for detecting toxoplasma antibody, recall rate is greatly improved, while avoiding false positive and missing inspection problem.

Description

A kind of recombinant protein composition for detecting toxoplasma antibody and preparation method thereof
Technical field
The present invention relates to technique for gene engineering and diagnostic reagent field, and in particular to one kind is used to detect wind toxoplasma antibody Recombinant protein composition and preparation method thereof.
Background technology
SAG1 and Microneme protein MIC2 are considered as having played important function in Infection of Toxoplasma Gondii infects host processes, immune Aspect SAG1 and MIC2 are considered as a kind of preferable diagnostic antigen, can be accurately quick, sensitively detect the sense of Infection of Toxoplasma Gondii Dye, so as to be furtherd investigate extensively.SAG1 is current most study and studies a kind of most deep memebrane protein, in the strain of different worms In have it is well-conserved, SAG1 can be expressed in prokaryotic expression system, eukaryotic expression system and insect expression system, can To be early diagnosed as diagnostic antigen.
MIC2 is that Infection of Toxoplasma Gondii invades the invasion factor that must exist during host cell, and place is connected in Infection of Toxoplasma Gondii Played a significant role during chief cell.MIC2 genes are conserved sequences, it is impossible to be knocked, and can weaken polypide after missing to place The invasive ability of chief cell.Although there is the recombinant protein for detecting toxoplasma antibody in currently available technology, still suffer from False positive and missing inspection problem, for above-mentioned problem, according to SAG1 and Microneme protein MIC2 property, can develop one The complex composition of the recombinant protein of SAG1 and Microneme protein MIC2 specificity epitopes is planted, for detecting toxoplasma antibody.
The content of the invention
It is an object of the invention to be:In view of the deficienciess of the prior art, providing a kind of high specificity, sensitivity is high, Recall rate, the recombinant protein composition of the detection toxoplasma antibody of reduction missing inspection can be improved.
To achieve these goals, the technical scheme is that:
It is a kind of detect toxoplasma antibody recombinant protein composition, the recombinant protein by SAG1 specific epitopes restructuring egg The recombinant protein composition of white and MIC2 specific epitopes.
As an improvement technical scheme, the recombinant protein of the SAG1 specific epitopes and the restructuring of MIC2 specific epitopes Albumen is mixed in the recombinant protein composition according to same concentrations, same ratio.
As an improvement technical scheme, the SAG1 specific epitopes are the 48th amino acid of SAG1 albumen n ends to 316 Individual amino acid, the MIC2 specific epitopes are the 75th amino acid of MIC2 albumen n ends to 468 amino acid.
It is another object of the present invention to be:Resist in view of the deficienciess of the prior art, providing a kind of detection Infection of Toxoplasma Gondii The preparation method of the recombinant protein composition of body.
To achieve these goals, the technical scheme is that:
A kind of preparation method for the recombinant protein composition for detecting toxoplasma antibody, the preparation method includes following step Suddenly:
(1) screening of toxoplasma antibody diagnostic antigen epitope
Using on-line analysis instrument, analysis Infection of Toxoplasma Gondii SAG1 and MIC2 amino acid sequence total length filter out Infection of Toxoplasma Gondii SAG1 protein-specifics antigen is located at the 48th amino acid to the 316th amino acid;Infection of Toxoplasma Gondii MIC2 protein-specifics antigen position In the 75th amino acid to the 468th amino acid;
(2) gene cloning of Infection of Toxoplasma Gondii SAG1 and MIC2 Protein Epitopes
Using bow-shaped worm dna as template, the gene piece of Infection of Toxoplasma Gondii SAG1 Protein Epitopes is expanded with SAG1 upstream and downstream primer Section;The genetic fragment of Infection of Toxoplasma Gondii MIC2 Protein Epitopes is expanded with MIC2 upstream and downstream primer;Electrophoresis glue reclaim purpose fragment ,- 20 DEG C freeze it is standby;
(3) SAG1 and MIC2 protein expression vectors are built respectively
PGEX-4T-1 and pGEX-4T-2 plasmids are extracted, pGEX-4T-1 and pGEX-4T-2 is distinguished after double digestion, electrophoresis The plasmid fragments of glue reclaim double digestion;Glue reclaim double digestion after Infection of Toxoplasma Gondii SAG1 albumen and MIC2 albumen difference double digestion, electrophoresis Purpose fragment;Double digestion plasmid and double digestion purpose fragment are pressed 1:3-10 ratios, with T4 ligases, 16 DEG C connect overnight, obtain Recombinant plasmid.
As an improvement technical scheme, the preparation method also comprises the following steps:
The screening and identification of recombinant plasmid:
Recombinant plasmid transformed e. coli bl21 (DE3) is coated with the LB flat boards containing ampicillin, 37 DEG C of constant temperature trainings Foster case is stayed overnight;Next day random picking conversion bacterium colony and control bacterium colony, extract plasmid, carry out double digestion, run electrophoresis, can see respectively See corresponding purpose fragment and carrier segments, as construction of expression vector success, positive expression bacterium;
Protein engineering bacterium high efficient expression:
Identification positive expression bacterium and control bacterium are seeded in the LB culture mediums containing ampicillin, 37 DEG C of constant-temperature tables shake Swing overnight, next day presses 1:100 inoculations, 37 DEG C of constant-temperature tables vibrate 4h, plus final concentration of 0.5-1mmol/l IPTG, 37 DEG C of continuation Induce 2-6h;Centrifugation, collects precipitation thalline, then will precipitate bacterial cell disruption, and the supernatant precipitation of collection carries out SDS-PAGE respectively Detection;It was found that the destination protein of pGEX-4T-1/SAG1 and pGEX-4T-2/MIC2 expression obtains respectively in supernatant The engineering bacteria of the SAG1 and MIC2 anti-genic fragment albumen of height expression;
The purifying of expressing protein:
The recombinant protein engineering bacteria of high efficient expression is centrifuged, precipitation thalline is collected, then precipitation thalline is resuspended in former centrifugation In 1/10 lysate of volume, bacterium solution supernatant is collected in ice-bath ultrasonic thalline, centrifugation;Take supernatant and 50% glutathione-sepharose Resin homogenate is well mixed, and supernatant is abandoned in centrifugation, and the PBS mixing collected precipitation and 8-12 times of normal volume is added into precipitation is equal It is even, centrifugation, then supernatant is abandoned, collect precipitation and the glutathione elution buffer of 1-3 times of volume is added into precipitation, mix, from The heart, the supernatant of collection is dialysed 24-48h in PBS, and centrifuging and taking supernatant obtains the antigenic purpose eggs of SAG1 and MIC2 respectively In vain, -20 DEG C it is standby.
As an improvement technical scheme, the amplification condition of step (2):Stage I:94℃3min;Stage II:94℃ 30s, 58 DEG C of 30s, 72 DEG C of 1min, 30 circulations;Stage III:72℃5min.
As an improvement technical scheme, SAG1 and MIC2 upstream and downstream primer has following institute respectively in step (2) The sequence shown:
SAG1 upstream primer sequences are:5’-AA GAATTC TCGGATCCCCCTCTTG-3’
SAG1 downstream primer sequences are:5’-AT CTCGAG ACTGGCTGTTCCCGCA-3’
MIC2 upstream primer sequences are:5’-AT CCCGGG CTGGACATTTGCTTTCTTAT-3’
MIC2 downstream primer sequences are:5’-AA CTCGAG TGGACACGGTGAGGTATT-3’.
As an improvement technical scheme, the recombinant plasmid in step (3) is pGEX-4T-1/SAG1 and pGEX-4T- 2/MIC2。
The present invention uses above technical scheme, compared with prior art, with advantages below:
Present invention selection two representational antigen proteins of SAG1 and MIC2, analyze two kinds of protein amino acid sequences, select The stronger partial segments of antigenicity, as the object of recombinant protein, substantially increase the yield and specificity of expression, by two kinds The recombinant protein composition that recombinant protein compounding is obtained has preferably specificity and sensitiveness, uses it for diagnosis Infection of Toxoplasma Gondii and resists Body, substantially increases clinical recall rate, efficiently solves the problems, such as false positive existing during detection and missing inspection.
Embodiment
In order to make the purpose , technical scheme and advantage of the present invention be clearer, the present invention is carried out further detailed Explanation.It should be appreciated that the specific embodiments described herein are merely illustrative of the present invention, it is not intended to limit the present invention.
Embodiment 1
A kind of recombinant protein composition for detecting toxoplasma antibody, it is special by the recombinant protein and MIC2 of SAG1 specific epitopes The recombinant protein of epitope mixes the recombinant protein of composition according to same concentrations, same ratio.Wherein SAG1 specific epitopes are SAG1 The 48th amino acid of albumen n end is to 316 amino acid, and MIC2 specific epitopes are the 75th amino acid of MIC2 albumen n ends to 468 Amino acid.
Embodiment 2
A kind of preparation method for diagnosing toxoplasma antibody recombinant antigen composition, comprises the following steps:
(1) screening of toxoplasma antibody diagnostic antigen epitope
Utilize the on-line analysis instrument such as ExPasy, TMHMM, SignalIP4.1, analysis Infection of Toxoplasma Gondii SAG1 and MIC2 amino Acid sequence total length, filters out Infection of Toxoplasma Gondii SAG1 protein-specifics antigen positioned at the 48th amino acid to the 316th amino acid;Arch Worm MIC2 protein-specifics antigen is located at the 75th amino acid to the 468th amino acid;
(2) gene cloning of Infection of Toxoplasma Gondii SAG1 and MIC2 Protein Epitopes
Design primer in SAG1 epitope DNA sequence dnas both sides
Sense primer 5-AA GAATTC TCGGATCCCCCTCTTG-3 '
EcoR I restriction enzyme sites
- AT CTCGAG the ACTGGCTGTTCCCGCA-3 ' of anti-sense primer 5 '
Xho I restriction enzyme sites
Design primer in MIC2 epitope DNA sequence dnas both sides
- AT CCCGGG the CTGGACATTTGCTTTCTTAT-3 ' of sense primer 5 '
Sma I restriction enzyme sites
- AA CTCGAG the TGGACACGGTGAGGTATT-3 ' of anti-sense primer 5 '
Xho I restriction enzyme sites
Using bow-shaped worm dna as template, the gene piece of Infection of Toxoplasma Gondii SAG1 Protein Epitopes is expanded with SAG1 upstream and downstream primers Section;The genetic fragment of Infection of Toxoplasma Gondii MIC2 Protein Epitopes is expanded with MIC2 upstream and downstream primers;Amplification condition:Stage I:94℃ 3min;Stage II:94 DEG C of 30s, 58 DEG C of 30s, 72 DEG C of 1min, 30 circulations;Stage III:72℃5min;Electrophoresis glue reclaim purpose Fragment, SAG1 purpose fragments be 823bp, MIC2 purpose fragments be 1198bp, -20 DEG C freeze it is standby;
(3) SAG1 and MIC2 protein expression vectors are built respectively
Extract pGEX-4T-1 and pGEX-4T-2 plasmids, pGEX-4T-1 EcoR I and Xho I double digestions, pGEX-4T-2 With Sma I and Xho I double digestions, the plasmid fragments of glue reclaim double digestion after electrophoresis;With EcoR I and Xho I double digestion Infection of Toxoplasma Gondii Glue reclaim after SAG1 albumen, Sma I and Xho I double digestion MIC2 albumen, electrophoresis, -20 DEG C standby;
Double digestion plasmid and double digestion purpose fragment press 1:3-10 ratios, with T4 ligases, 16 DEG C connect overnight.After connection Recombinant vector be pGEX-4T-1/SAG1 and pGEX-4T-2/MIC2 respectively;
(4) screening and identification of recombinant plasmid
By recombinant plasmid transformed e. coli bl21 (DE3), coating contains on ampicillin (50ug/ml) LB flat boards, and 37 DEG C constant incubator is stayed overnight.5 conversion bacterium colonies of next day random picking and 2 control bacterium colonies (plasmid PGEX-4T-1 and pGEX-4T- 2) plasmid, is extracted respectively, and pGEX-4T-1/SAG1 and pGEX-4T-2/MIC2 use EcoR I/Xho I and Sma I/Xho I respectively Electrophoresis is run after double digestion, digestion.Corresponding purpose fragment and carrier segments can be seen, construction of expression vector success is sun Property expression bacterium;And purpose fragment is not seen after compareing bacteria plasmid digestion;
(5) protein engineering bacterium high efficient expression
The bacterium and control bacterium that identify positive expression are seeded to the test tube of 2mlLB culture mediums (60ug/ml ampicillins) In, 37 DEG C of constant-temperature table shaken overnights, next day presses 1:100 inoculations, 37 DEG C of constant-temperature tables vibration 4h, plus IPTG are (final concentration of 1mmol/l), 37 DEG C of induction 4h are continued;Bacterium solution is collected by centrifugation, supernatant precipitation carries out SDS-PAGE detections after crushing;It was found that The destination protein of pGEX-4T-1/SAG1 and pGEX-4T-2/MIC2 expression is in supernatant;Compare in bacterium without destination protein bar Band, illustrates the engineering bacteria for obtaining SAG1 the and MIC2 anti-genic fragment albumen of high expression respectively;
(6) purifying of expressing protein
(4 DEG C) of (10000rpm) low temperature centrifuges 10min to the recombinant protein engineering bacteria of high efficient expression at a high speed, by the thalline of precipitation In 1/10 lysate (50mM Tris-Hcl, 10mM EDTA, 15mM NaCL, 10mM DTT) for being resuspended in former centrifugation volume, ice The ultrasonic thalline 20min of bath, (4 DEG C) centrifugation 30min of (12000rpm) low temperature, collect bacterium solution supernatant at a high speed;
The homogenate of supernatant and 50% Glutathione-agarose resin is mixed, at room temperature jog 30min, mixture in 4 DEG C from 5min is centrifuged under 2100rpm/min rotating speeds in scheming, abandons in supernatant, the precipitation of collection and adds the PBS of 10 times of normal volumes, overturn (washing away the albumen not with resin-bonded) is mixed for several times, mixture is centrifuged in 4 DEG C of centrifuges under 2100rpm/min rotating speeds 5min, is abandoned in supernatant, the precipitation of collection and adds the glutathione elution buffer of 1 times of volume, and ambient temperature with gentle agitation 10min (is washed The albumen combined in deresination), 5min is centrifuged under 4 DEG C of 2100rpm/min rotating speeds, supernatant is moved in new pipe, is repeated 2 times, merge 3 Secondary supernatant, the dialysis 48h in PBS (10mM, PH7.4), centrifuging and taking supernatant obtains the antigenic purpose eggs of SAG1 and MIC2 respectively In vain, -20 DEG C it is standby.
The positive expression bacterium recombinant plasmid of embodiment 3 is sequenced
Above-mentioned positive expression bacterium is extracted into plasmid with plasmid extraction kit to send in Shanghai life work sequencing.
The DNA sequence dna of SAG1 genetic fragments in recombinant plasmid is completely correct, as a result as follows:
TCGGATCCCCCTCTTGTTGCCAATCAAGTTGTCACCTGCCCAGATAAAAAATCGACAGCCGCGGTCATT CTCACACCGACGGAGAACCACTTCACTCTCAAGTGCCCTAAAACAGCGCTCACAGAGCCTCCCACTCTTGCGTACTC ACCCAACAGGCAAATCTGCCCAGCGGGTACTACAAGTAGCTGTACATCAAAGGCTGTAACATTGAGCTCCTTGATTC CTGAAGCAGAAGATAGCTGGTGGACGGGGGATTCTGCTAGTCTCGACACGGCAGGCATCAAACTCACAGTTCCAATC GAGAAGTTCCCCGTGACAACGCAGACGTTTGTGGTCGGTTGCATCAAGGGAGACGACGCACAGAGTTGTATGGTCAC AGTGACAGTACAAGCCAGAGCCTCATCGGTCGTCAATAATGTCGCAAGGTGCTCCTACGGTGCAGACAGCACTCTTG GTCCTGTCAAGTTGTCTGCGGAAGGACCCACTACAATGACCCTCGTGTGCGGGAAAGATGGAGTCAAAGTTCCTCAA GACAACAATCAGTACTGTTCCGGGACGACGCTGACTGGTTGCAACGAGAAATCGTTCAAAGATATTTTGCCAAAATT AACTGAGAACCCGTGGCAGGGTAACGCTTCGAGTGATAAGGGTGCCACGCTAACGATCAAGAAGGAAGCATTTCCAG CCGAGTCAAAAAGCGTCATTATTGGATGCACAGGGGGATCGCCTGAGAAGCATCACTGTACCGTGAAACTGGAGTTT GCCGGGGCTGCAGGGTCAGCAAAATCGGCTGCGGGAACAGCCAGT
The DNA sequence dna of MIC2 genetic fragments in recombinant plasmid is completely correct, as a result as follows:
CTGGACATTTGCTTTCTTATCGATTCGTCTGGAAGCATAGGAATACAGAATTTCCGTCTAGTAAAACAGTTCCTCCA CACCTTTTTAATGGTGTTGCCCATTGGCCCAGAAGAAGTTAACAATGCAGTTGTTACTTACTCGACGGACGTTCACC TGCAATGGGATCTACAGAGTCCGAACGCGGTTGACAAGCAGCTCGCGGCGCATGCGGTGCTAGACATGCCGTATAAA AAGGGCAGTACCAACACCAGTGATGGACTGAAGGCCTGCAAACAAATTCTGTTTACAGGTTCGCGCCCAGGACGCGA ACATGTGCCGAAGCTAGTGATTGGAATGACAGATGGCGAATCGGATTCTGATTTTCGCACCGTGAGAGCGGCAAAGG AGATTCGTGAGCTTGGAGGCATCGTCACAGTCCTTGCAGTCGGTCATTACGTCAAACATAGTGAGTGCCGAAGCATG TGTGGGTGCAGTGGTACGAGCGATGATGACAGTCCGTGTCCCCTGTATCTTCGGGCTGACTGGGGGCAGCTCGCGAC GGCGATTAAACCGATGCTTAAAGAGGTTTGTAAGACACTCCCCCAGGATGCCATTTGCTCGGATTGGTCCGCATGGA GCCCCTGCAGTGTATCCTGCGGTGACGGAAGCCAAATCAGGACGCGAACTGAGGTTTCTG CTCCGCAACCTGGAACACCAACATGTCCGGACTGCCCTGCGCCCATGGGAAGGACTTGCGTGGAACAAGGCGGACTT GAAGAAATTCGTGAATGCAGTGCGGGGGTATGTGCTGTTGACGCTGGATGTGGCGTCTGGGGAGAGTGGTCCGCCTG GAGCGCGTCTTGCGGAAATGCCACAAGGAAGCGAGAGCGAACGCGTTACAATGACCCACCACCCCAGGGGGCAGGCC GTCGGTGTGAAAATCAGGATCCGCCGGTGTTACAGGAGCAGACAGAAGAAGCAACTCTTGCTCCTTGCATAACTATA CCGCCAACTCCCCCAGAATGGGCTGCATGGAGCGACTGCACTGTCACGTGTGGCGGTGGCAATCGGCATCGAGTGAG AAACGCACTGCCACCAGGACTGGGGTCGCAGAACGGAGAAAGTGACGAATCGCTCGTGTCCAAACTGTGGCCTGGGA CAGATCTACGACAGGAGGAAGCATGTAATACCTCACCGTGTCCA
The recombinant protein detection toxoplasma antibody of the purifying of embodiment 4
By 1 under 2 kinds of recombinant protein comparable sodiums of purifying:1 mixing, after being diluted with carbonate buffer solution (50mM, PH9.6) 100ul/ holes, the protein content coating elisa plate in 100ng/ holes, 4 DEG C overnight.Add the PBS of the calf serum of 200ul/ holes 10% after washing 2h are closed in 37 DEG C of water-baths, after washing 4 DEG C it is standby.
Dot-ELISA detects 5 parts of resisting toxoplasmosis positive serums and 5 portions of normal human serums.Surveyed using 450nm wavelength Determine OD values.As a result display (being shown in Table 1) fusion protein compositions can react with 5 parts of resisting toxoplasmosis positive serums, not with 5 parts of normal persons Seroreaction, illustrates that said composition has preferably antigenicity and specificity.
The Dot-ELISA experimental result of table 1 (A450 values)
1 2 3 4 5
Resisting toxoplasmosis IgM positive serums 1.286 1.471 1.869 1.366 1.881
Normal human serum 0.021 0.019 0.035 0.028 0.033
This patent is not limited to above-mentioned specific embodiment, one of ordinary skill in the art from above-mentioned design, Without performing creative labour, made a variety of conversion are all fallen within the protection domain of this patent.
SEQUENCE LISTING
<110>Weifang Hightop Biotech Co., Ltd.
<120>A kind of recombinant protein composition for detecting toxoplasma antibody and preparation method thereof
<130> 1
<160> 6
<170> PatentIn version 3.5
<210> 1
<211> 807
<212> DNA
<213>The gene order of SAG1 specific epitopes
<400> 1
tcggatcccc ctcttgttgc caatcaagtt gtcacctgcc cagataaaaa atcgacagcc 60
gcggtcattc tcacaccgac ggagaaccac ttcactctca agtgccctaa aacagcgctc 120
acagagcctc ccactcttgc gtactcaccc aacaggcaaa tctgcccagc gggtactaca 180
agtagctgta catcaaaggc tgtaacattg agctccttga ttcctgaagc agaagatagc 240
tggtggacgg gggattctgc tagtctcgac acggcaggca tcaaactcac agttccaatc 300
gagaagttcc ccgtgacaac gcagacgttt gtggtcggtt gcatcaaggg agacgacgca 360
cagagttgta tggtcacagt gacagtacaa gccagagcct catcggtcgt caataatgtc 420
gcaaggtgct cctacggtgc agacagcact cttggtcctg tcaagttgtc tgcggaagga 480
cccactacaa tgaccctcgt gtgcgggaaa gatggagtca aagttcctca agacaacaat 540
cagtactgtt ccgggacgac gctgactggt tgcaacgaga aatcgttcaa agatattttg 600
ccaaaattaa ctgagaaccc gtggcagggt aacgcttcga gtgataaggg tgccacgcta 660
acgatcaaga aggaagcatt tccagccgag tcaaaaagcg tcattattgg atgcacaggg 720
ggatcgcctg agaagcatca ctgtaccgtg aaactggagt ttgccggggc tgcagggtca 780
gcaaaatcgg ctgcgggaac agccagt 807
<210> 2
<211> 1182
<212> DNA
<213>The gene order of MIC2 specific epitopes
<400> 2
ctggacattt gctttcttat cgattcgtct ggaagcatag gaatacagaa tttccgtcta 60
gtaaaacagt tcctccacac ctttttaatg gtgttgccca ttggcccaga agaagttaac 120
aatgcagttg ttacttactc gacggacgtt cacctgcaat gggatctaca gagtccgaac 180
gcggttgaca agcagctcgc ggcgcatgcg gtgctagaca tgccgtataa aaagggcagt 240
accaacacca gtgatggact gaaggcctgc aaacaaattc tgtttacagg ttcgcgccca 300
ggacgcgaac atgtgccgaa gctagtgatt ggaatgacag atggcgaatc ggattctgat 360
tttcgcaccg tgagagcggc aaaggagatt cgtgagcttg gaggcatcgt cacagtcctt 420
gcagtcggtc attacgtcaa acatagtgag tgccgaagca tgtgtgggtg cagtggtacg 480
agcgatgatg acagtccgtg tcccctgtat cttcgggctg actgggggca gctcgcgacg 540
gcgattaaac cgatgcttaa agaggtttgt aagacactcc cccaggatgc catttgctcg 600
gattggtccg catggagccc ctgcagtgta tcctgcggtg acggaagcca aatcaggacg 660
cgaactgagg tttctgctcc gcaacctgga acaccaacat gtccggactg ccctgcgccc 720
atgggaagga cttgcgtgga acaaggcgga cttgaagaaa ttcgtgaatg cagtgcgggg 780
gtatgtgctg ttgacgctgg atgtggcgtc tggggagagt ggtccgcctg gagcgcgtct 840
tgcggaaatg ccacaaggaa gcgagagcga acgcgttaca atgacccacc accccagggg 900
gcaggccgtc ggtgtgaaaa tcaggatccg ccggtgttac aggagcagac agaagaagca 960
actcttgctc cttgcataac tataccgcca actcccccag aatgggctgc atggagcgac 1020
tgcactgtca cgtgtggcgg tggcaatcgg catcgagtga gaaacgcact gccaccagga 1080
ctggggtcgc agaacggaga aagtgacgaa tcgctcgtgt ccaaactgtg gcctgggaca 1140
gatctacgac aggaggaagc atgtaatacc tcaccgtgtc ca 1182
<210> 3
<211> 24
<212> DNA
<213>SAG1 upstream primer sequences
<400> 3
aagaattctc ggatccccct cttg 24
<210> 4
<211> 24
<212> DNA
<213>SAG1 downstream primer sequences
<400> 4
atctcgagac tggctgttcc cgca 24
<210> 5
<211> 28
<212> DNA
<213>MIC2 upstream primer sequences
<400> 5
atcccgggct ggacatttgc tttcttat 28
<210> 6
<211> 26
<212> DNA
<213>MIC2 downstream primer sequences
<400> 6
aactcgagtg gacacggtga ggtatt 26

Claims (8)

1. a kind of recombinant protein composition for detecting toxoplasma antibody, it is characterised in that:The recombinant protein composition is by SAG1 The recombinant protein of specific epitopes and the recombinant protein composition of MIC2 specific epitopes.
2. a kind of recombinant protein composition for detecting toxoplasma antibody according to claim 1, it is characterised in that:It is described The recombinant protein of SAG1 specific epitopes and the recombinant protein of MIC2 specific epitopes are in the recombinant protein composition according to identical Concentration, same ratio mixing.
3. a kind of recombinant protein composition for detecting toxoplasma antibody according to claim 1, it is characterised in that:It is described SAG1 specific epitopes are the 48th amino acid of SAG1 albumen n ends to 316 amino acid, and the MIC2 specific epitopes are MIC2 albumen The 75th amino acid of N-terminal is to 468 amino acid.
4. a kind of preparation method for the recombinant protein composition for detecting toxoplasma antibody, it is characterised in that the preparation method includes The following steps:
(1) screening of toxoplasma antibody diagnostic antigen epitope
Using on-line analysis instrument, analysis Infection of Toxoplasma Gondii SAG1 and MIC2 amino acid sequence total length filter out Infection of Toxoplasma Gondii SAG1 eggs White specific antigen is located at the 48th amino acid to the 316th amino acid;Infection of Toxoplasma Gondii MIC2 protein-specifics antigen is located at the 75th Individual amino acid is to the 468th amino acid;
(2) gene cloning of Infection of Toxoplasma Gondii SAG1 and MIC2 Protein Epitopes
Using bow-shaped worm dna as template, the genetic fragment of Infection of Toxoplasma Gondii SAG1 Protein Epitopes is expanded with SAG1 upstream and downstream primer; The genetic fragment of Infection of Toxoplasma Gondii MIC2 Protein Epitopes is expanded with MIC2 upstream and downstream primer;Electrophoresis glue reclaim purpose fragment, -20 DEG C freeze standby;
(3) SAG1 and MIC2 protein expression vectors are built respectively
PGEX-4T-1 and pGEX-4T-2 plasmids are extracted, pGEX-4T-1 and pGEX-4T-2 is distinguished into glue after double digestion, electrophoresis and returned Receive the plasmid fragments of double digestion;Glue reclaim double digestion purpose after Infection of Toxoplasma Gondii SAG1 albumen and MIC2 albumen difference double digestion, electrophoresis Fragment;Double digestion plasmid and double digestion purpose fragment are pressed 1:3-10 ratios, with T4 ligases, 16 DEG C connect overnight, are recombinated Plasmid.
5. a kind of preparation method of recombinant protein composition for detecting toxoplasma antibody according to claim 4, its feature It is that the preparation method comprises the following steps:
The screening and identification of recombinant plasmid:
By recombinant plasmid transformed e. coli bl21 (DE3), it is coated with the LB flat boards containing ampicillin, 37 DEG C of constant incubators Overnight;Next day random picking conversion bacterium colony and control bacterium colony, extract plasmid, carry out double digestion, run electrophoresis, can see phase respectively The purpose fragment and carrier segments answered, as construction of expression vector success, positive expression bacterium;
Protein engineering bacterium high efficient expression:
Identification positive expression bacterium and control bacterium are seeded in the LB culture mediums containing ampicillin, 37 DEG C of constant-temperature tables vibrated Night, next day presses 1:100 inoculations, 37 DEG C of constant-temperature tables vibrate 4h, plus final concentration of 0.5-1mmol/l IPTG, and 37 DEG C are continued to induce 2-6h;Centrifugation, collects precipitation thalline, then will precipitate bacterial cell disruption, and the supernatant precipitation of collection carries out SDS-PAGE detections respectively; It was found that the destination protein of pGEX-4T-1/SAG1 and pGEX-4T-2/MIC2 expression obtains high expression respectively in supernatant SAG1 and MIC2 anti-genic fragment albumen engineering bacteria;
The purifying of expressing protein:
The recombinant protein engineering bacteria of high efficient expression is centrifuged, precipitation thalline is collected, then precipitation thalline is resuspended in former centrifugation volume 1/10 lysate in, ice-bath ultrasonic thalline, centrifugation, collect bacterium solution supernatant;Take supernatant and 50% Glutathione-agarose resin Homogenate is well mixed, centrifugation, abandons supernatant, and the PBS for collecting precipitation and 8-12 times of normal volume being added into precipitation is well mixed, from The heart, then supernatant is abandoned, collect precipitation and the glutathione elution buffer of 1-3 times of volume is added into precipitation, mix, centrifuge, receive The supernatant of collection is dialysed 24-48h in PBS, centrifuging and taking supernatant, i.e., obtain the antigenic destination proteins of SAG1 and MIC2, -20 DEG C respectively It is standby.
6. a kind of preparation method of recombinant protein composition for detecting toxoplasma antibody according to claim 4, its feature It is:The amplification condition of step (2):Stage I:94℃3min;Stage II:94 DEG C of 30s, 58 DEG C of 30s, 72 DEG C of 1min, 30 are followed Ring;Stage III:72℃5min.
7. a kind of preparation method of recombinant protein composition for detecting toxoplasma antibody according to claim 4, its feature It is:SAG1 and MIC2 upstream and downstream primer has sequence as follows respectively in step (2):
SAG1 upstream primer sequences are:5’-AA GAATTC TCGGATCCCCCTCTTG-3’
SAG1 downstream primer sequences are:5’-AT CTCGAG ACTGGCTGTTCCCGCA-3’
MIC2 upstream primer sequences are:5’-AT CCCGGG CTGGACATTTGCTTTCTTAT-3’
MIC2 downstream primer sequences are:5’-AA CTCGAG TGGACACGGTGAGGTATT-3’.
8. a kind of preparation method of recombinant protein composition for detecting toxoplasma antibody according to claim 4, its feature It is:Recombinant plasmid in step (3) is pGEX-4T-1/SAG1 and pGEX-4T-2/MIC2.
CN201710507519.2A 2017-06-28 2017-06-28 A kind of recombinant protein composition for detecting toxoplasma antibody and preparation method thereof Withdrawn CN107253983A (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108503707A (en) * 2018-03-23 2018-09-07 浙江省医学科学院 The nano antibody and its encoding gene of a kind of resisting toxoplasmosis SAG1 and application
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