KR19980069019A - Protease Proteins Derived from Nonstructural Protein 3 of the Korean Hepatitis C Virus and Methods of Manufacturing the Same - Google Patents

Abstract

The present invention relates to a truncated recombinant protein consisting of 213 amino termini of the amino terminus corresponding to a protease site derived from 631 non-structural protein 3 of hepatitis C virus, and a method for producing the same.

More specifically, the present invention relates to a protease protein which is part of non-structural protein 3 involved in the proliferation of Korean hepatitis C virus, an expression vector capable of producing it in E. coli, and a protease of hepatitis C virus using the same. The non-structural protein 3Δ) is produced in E. coli, and the protease protein of the present invention can be easily isolated and purified, including histidine label, and widely used for screening proliferation inhibitor of hepatitis C virus. have.

Description

Protease Proteins Derived from Nonstructural Protein 3 of the Korean Hepatitis C Virus and Methods of Manufacturing the Same

The present invention relates to a protease protein derived from the nonstructural protein 3 of hepatitis C virus and a method for producing the same.

More specifically, the present invention relates to a protease protein which is part of non-structural protein 3 involved in the proliferation of Korean hepatitis C virus, an expression vector capable of producing it in E. coli, and a protease of hepatitis C virus using the same. The non-structural protein 3Δ) is produced in E. coli, and the protease protein of the present invention can be easily isolated and purified, including histidine label, and widely used for screening proliferation inhibitor of hepatitis C virus. have.

Hepatitis C Virus is a major cause of hepatitis known to cause non-A or non-B hepatitis, which not only invades humans and causes acute or chronic hepatitis, but also leads to cirrhosis or liver cancer. (Alter, HJ et al., 1989, N. Eng. J. Med, 321: 1494-1500). Hepatitis C virus has been reported to infect 1% of the world's population, with an estimated one million new cases of hepatitis C virus per year (Purcell, 1994, FEMS Microbial. Rev). , 14: 181-192; van der Poel, 1994, Hepatitis C Virus: Current Studies in Hematology and Blood Transfusion, HW Reesink ed., Pp. 137-193; Alter, HJ, 1988, AJ Zuckerman ed., Viral Hepatitis and Liver Disease, pp. 537-542). In addition, about 40-50% of patients infected with hepatitis C virus become chronic hepatitis patients, and about 20% become more advanced and become cirrhosis or liver cancer patients (Dienstag, JL, 1986). , Semin.Liver.Dis, 6: 67-81).

Hepatitis C virus can be recovered by inoculating chimpanzees with plasma from non-Hepatitis A or non-B hepatitis patients (Bradley, D. W. et al., 1988, Gatroenterology, 88: 773-779). The hepatitis C virus thus obtained has a gene in the form of a positive strand ribonucleic acid consisting of 9400 bases, from which a polyprotein consisting of 3010-3033 amino acids is produced (Choo, QL et al., 1989, Science). , 244: 359-362, Choo, QL et al., 1991, PNAS, 88: 2451-2455). Considering the gene structure described above, hepatitis C virus is similar to flaviviruses or pestiviruses, so hepatitis C virus is classified as a new genus belonging to Flaviviridae. (Van Doorn, 1994, review. J. Med. Virol, 43: 345-356).

The polyprotein of hepatitis C virus consists of the amino-terminus from Core-E1-E2-NS2-NS3 -NS4A-NS4B-NS5A-NS5B. That is, at the amino terminus of the polyprotein, there are structural proteins (core, E1, E2), which are components of the nucleocapsid and envelope of the virus, and the hepatitis C virus proliferates at the carboxy terminus thereof. Essential nonstructural proteins (NS2, NS3, NS4A, NS4B, NS5A, NS5B) are located. This polyprotein is synthesized by intracellular signal peptidase and non-structural protein 2-3 and non-structural protein 3, which are proteases present in the virus, to cut 9 specific sites of the precursor polyprotein. Produce viral proteins. Specifically, nonstructural protein 3 has been shown to act on four cleavage sites present between nonstructural proteins 3 and 4A, between 4A and 4B, between 4B and 5A, and between 5A and 5B (Hijikata, et al., 1991 , PNAS, 88: 5547-5551, Bartenschlarger, et al., 1994, J. Virol, 68: 5045-5055, Grakoui, et al., 1993, J. Virol, 67: 1385-95, Tomei, et al. , 1993, J. Virol, 67: 4017-4026).

A universal treatment for effectively treating chronic infection of hepatitis C virus has not been developed yet, and almost the only administration of interferon-alpha as a therapeutic agent for hepatitis C virus is carried out. However, when interferon-alpha is administered to hepatitis C patients, only 15-20% of patients show therapeutic effect (Hoofnagal, J. H., 1994, And. Intern. Med., 39: 241-275). It is also the most widely found type of virus in the world, especially in Asia, the Americas, and Europe, causing hepatitis C, and its effect is low on hepatitis C virus-1b, which has a high rate of progression to cirrhosis or liver cancer. There is a problem that cannot be widely used to treat hepatitis caused by hepatitis virus (van Doorn, LJ, 1994, review, J. Med. Virol. 43: 345-356). Therefore, it is very important to develop new treatments for the infection of hepatitis C virus.

Nonstructural protein 3 of hepatitis C virus plays a very important role in cleaving precursor polyproteins to produce mature nonstructural proteins 3, 4A, 4B, 5A and 5B (Kim, JL et al., 1996, Cell, 87: 343-355). This nonstructural protein 3 is composed of a serine protease, nucleotide dephosphatase (NTPase), and an amino acid motif that exhibits RNA helicase activity in a single protein, and the helicase function is present at the carboxy terminus. Degradase function is known to be present at the amino terminus (Kim, et al., 1995, BBRC 215: 160-165, Han et al., 1995, J. Gen. Virol 76: 985-993). Therefore, by removing the carboxy terminus of the nonstructural protein 3 of hepatitis C virus, only its protease site can be obtained. During the proliferation of hepatitis C virus, the protease active site of the nonstructural protein 3 plays an important role in the production of viral particles by cleaving polyprotein. Therefore, the enzyme can be obtained as an independent protein and screened for inhibitors. If possible, an effective treatment for hepatitis C can be easily developed.

Therefore, the present inventors produced 213 amino terminus amino acids corresponding to proteolytic enzyme sites derived from nonstructural protein 3 consisting of 631 amino acids of hepatitis C virus, which can be used to develop an effective hepatitis C therapeutic agent. To this end, a polymerase chain reaction is carried out using a viral gene as a template to obtain only the protease gene region of the nonstructural protein 3, which is then cloned into an expression vector capable of producing a recombinant protein with a histidine label added to its amino terminus. The present invention was completed by mass-producing the protease protein (hereinafter, abbreviated nonstructural protein 3Δ) in Escherichia coli using an expression vector and separating and purifying it by a histidine-labeled affinity column.

An object of the present invention is to provide a protease protein derived from the nonstructural protein 3 of hepatitis C virus.

Specifically, the present invention provides a protease present in the amino terminus of the nonstructural protein 3 of the Korean hepatitis C virus in an independent protein form. The present invention also provides a protease protein comprising a histidine label at the amino terminus.

Another object of the present invention is to provide an expression vector for producing protease protein of Korean hepatitis C virus in E. coli. Specifically, the present invention provides an expression vector pRSET-NS3Δ to produce the protease protein in the form of a histidine-labeled protein.

In addition, the present invention provides an E. coli transformant (Accession No .: KCTC 8779P) in which the expression vector pRSET-NS3Δ is transformed into E. coli.

In addition, the present invention provides a method for obtaining the protease protein by culturing the transformant to induce the expression of the protease protein and to obtain the crude cell eluate therefrom to perform histidine-labeled affinity chromatography. There is a purpose.

In addition, the protease protein of the hepatitis C virus obtained in the present invention can be used to select a proliferation inhibitor and protease inhibitor of the virus, and if applied to the effective therapeutic agents such as hepatitis C, liver cirrhosis and liver cancer caused by hepatitis C virus Can be developed.

Figure 1 shows the manufacturing process of the expression vector pRSET-NS3Δ producing a protease protein (non-structural protein 3Δ) of the Korean type hepatitis C virus of the present invention.

Figure 2a is a polyacrylamide gel electrophoresis by separating and purifying the protease protein (non-structural protein 3Δ) of the Korean type hepatitis C virus produced by E. coli BL21 (DE3) transformed with the expression vector pRSET-NS3Δ of the present invention One result is shown.

Lane 1: standard molecular weight labeled protein

Lane 2: total cell lysate (TCL) before purification

Lanes 3-6: eluted fractions

Figure 2b shows the results of Western blot separation and purification of the protease protein (non-structural protein 3Δ) of the Korean hepatitis C virus produced by E. coli BL21 (DE3) transformed with the expression vector pRSET-NS3Δ of the present invention will be.

Lane 1: standard molecular weight labeled protein

Lane 2: nonstructural protein 3Δ

The present invention provides a new protease derived from nonstructural protein 3 of hepatitis C virus (hereinafter abbreviated as nonstructural protein 3Δ). Specifically, the present invention provides only the protease active site present in the amino terminus of the nonstructural protein 3 involved in polyprotein maturation of the Korean hepatitis C virus in an independent protein form.

At this time, the Korean hepatitis C virus is obtained from the sera of a Korean hepatitis C patient, and its gene is different from the existing US and Japanese hepatitis C viruses, so it is called a Korean hepatitis C virus.

The present invention inserts a protease site gene located at the 5′-end of the nonstructural protein 3 gene into an expression vector and expresses it in E. coli to produce a large amount of protease protein of hepatitis C virus.

Therefore, the present invention produces an expression vector capable of producing protease protein derived from nonstructural protein 3 of hepatitis C virus in E. coli.

Specifically, the present invention is obtained by performing a polymerase chain reaction of the 5'-terminal gene containing the protease site gene from the nonstructural protein 3 gene of the Korean hepatitis C virus. At this time, oligonucleotides having the nucleotide sequences of SEQ ID NO: 1 and SEQ ID NO: 2 are synthesized and used as primers (see SEQ ID NO: 1 and SEQ ID NO: 2). Specifically, the primer of SEQ ID NO: 1 has a restriction enzyme Nhe I recognition site (GCTAGC) and comprises a base sequence encoding amino acids 1027 to 1032 on the polyprotein of the Korean hepatitis C virus, The primer has a restriction enzyme Eco RI recognition site (GAATTC) and one end codon and comprises amino acids 1235 to 1239 on the Korean hepatitis C virus polyprotein.

The expression vector of the present invention was prepared by inserting the nonstructural protein 3Δ gene of the hepatitis C virus obtained by the above procedure into an E. coli expression vector pRSET-A comprising a T7 promoter and six histidine base sequences (see FIG. 1). ).

Specifically, the nonstructural protein 3Δ gene includes a restriction enzyme recognition site at the 5′-end to facilitate cloning into an E. coli expression vector, and the corresponding 3′-end includes a termination codon and a restriction enzyme recognition site. The expression vector of the invention is constructed such that synthesis of the protein at the start codon is initiated, the nonstructural protein 3Δ comprising 6 histidines is expressed, and then the synthesis of the protein is completed at the artificially inserted end codon.

The expression vector of the present invention was named pRSET-NS3Δ and transformed into Escherichia coli, and the transformant was deposited on January 29, 1997 with the Gene Bank of Korea Institute of Science and Technology, Biotechnology Research Institute (Accession Number: KTCT 8779P). ).

The present invention also provides a method for obtaining a nonstructural protein 3Δ derived from the Korean hepatitis C virus using the expression vector and E. coli transformants prepared above.

Specifically, in order to express the non-structural protein 3Δ using the E. coli transformant transformed with the E. coli expression vector pRSET-NS3Δ, cultivation was carried out using an ampicillin-containing liquid Luria medium, followed by induction of the expression of the protein. do. Next, E. coli cells are expressed by crushing E. coli cells expressing the recombinant protein.

Since the non-structural protein 3Δ of the Korean hepatitis C virus prepared above contained six histidine labels at its amino terminus, it was isolated and purified using histidine-labeled affinity column chromatography. At this time, it is preferable to use an imidazole concentration gradient as the elution solvent. Histidine labeling not only facilitates the separation and purification of the expressed nonstructural protein 3Δ by affinity column chromatography, etc., but also maintains the enzymatic activity of the protein during purification.

The molecular weight and purity of the non-structural protein 3Δ of the Korean type hepatitis C virus isolated and purified above are confirmed by performing polyacrylamide gel electrophoresis and Western blot (see FIGS. 2A and 2B).

Hereinafter, the present invention will be described in more detail based on the following examples. However, the following examples are only for illustrating the present invention, and the present invention is not limited thereto.

Example 1 Preparation of Expression Vector of Korean Hepatitis C Virus Nonstructural Protein 3Δ

(Step 1) Synthesis of primer for polymerase chain reaction

To obtain the gene of the nonstructural protein 3Δ region of the Korean hepatitis C virus, a primer for polymerase chain reaction was synthesized using a nucleic acid synthesizer (DNA synthesizer, Applied Biosystems Inc. USA). By using the DNA sequence of the virus (Korean Patent Application No. 93-9913) is designed to include the base sequence corresponding to the 5'-end and 3'-end of the gene encoding the nonstructural protein 3Δ site.

Specifically, the primer of SEQ ID NO: 1 has a restriction enzyme Nhe I recognition site (GCTAGC) and was designed to have a nucleotide sequence encoding amino acids 1027 to 1032 of the Korean hepatitis C virus, and the primer of SEQ ID NO: 2 is a restriction enzyme. It was designed to have the Eco RI recognition site (GAATTC) and one end codon and have 1235th to 1239th amino acids on the polyprotein of Korean hepatitis C virus.

(Step 2) Amplification of the nonstructural protein 3Δ gene of Korean hepatitis C virus

To amplify the nonstructural protein 3Δ gene of Korean hepatitis C virus, a polymerase chain reaction was performed as follows. Into the reaction tube, the primer of 100 pmole SEQ ID NO: 1 and the primer of 100 pmole SEQ ID NO: 2 obtained in the above (Step 1) were placed, and the plasmid vector M13-KHCV-L2 (Korean Patent Application No. 93-9913, Accession No. ATCC) was used as a template. 75447), then 10 μl of 10-fold polymerization buffer (500 mM potassium chloride, 100 mM tris-hydrochloric acid pH 9.0, 1% Triton X-100, 2.5 mM magnesium chloride), 10 μl of 2 mM dNTP, 2.5 units of Taq polymerase After distilled water was added to 100 µl of total volume, the polymerase chain reaction was carried out under the conditions of 1 minute (denatured step) at 95 ° C, 1 minute (immersion step) at 55 ° C, and 2 minutes (polymerization step) at 72 ° C. 25 times. The resulting nucleic acid fragments were isolated on a 7% polyacrylamide gel and confirmed to have amplified 0.7 kb base pair nucleic acids, which were then cleaned from a 2% agarose gel (Gene clean II kit, Bio 101, USA). ) Was isolated and purified to obtain a nucleic acid fragment of about 0.7kb containing a nonstructural protein 3Δ gene.

(Step 3) Preparation of an E. coli expression vector containing a nonstructural protein 3Δ gene of Korean hepatitis C virus

To prepare the expression vector of the present invention, 3 μg of the plasmid vector pRSET-A (Invitrogen, USA) was added to BM (Beringermannheim, Germany) buffer solution (10 mM Tris-HCl pH 7.5, 10 mM magnesium chloride, 50 mM sodium chloride, 1 mM dithiothreitol) and digestion with restriction enzyme Nhe I, complete digestion with restriction enzyme Eco RI in Gibco buffer (50 mM Tris-HCl pH 8.0, 10 mM magnesium chloride, 100 mM sodium chloride) and 1 Electrophoresis was performed on a% agarose gel to obtain a nucleic acid fragment of a 2.9 kb plasmid vector.

Meanwhile, 5 μg of the nucleic acid fragment containing the nonstructural protein 3Δ gene obtained in step (2) was digested with restriction enzyme Nhe I in BM buffer solution, and completely digested with restriction enzyme Eco RI in Gibco buffer solution, and then 0.7. Nucleic acid fragments of the gene were obtained in kb size.

Into the conjugation reaction vessel, 100 ng of the 2.9 kb plasmid vector nucleic acid fragment and 100 ng of the 0.7 kb nonstructural protein 3Δ nucleic acid fragment were placed. Oreitol, 1 mM ATP, 25 μg / ml bovine serum albumin) and 10 units of T4 DNA ligase were added, and distilled water was added so that the total volume was 20 μl and reacted at 16 ° C. for 12 hours. After the conjugation reaction, E. coli HB101 cells were transformed, and then transformants were selected on Luria agar plates containing 50 μg / ml of ampicillin and extracted expression vectors therefrom. It was confirmed that the E. coli expression vector pRSET-NS3Δ was obtained. Figure 1 illustrates the process for producing the expression vector pRSET-NS3Δ.

The E. coli transformant (BL21 (DE3) / pRSET-NS3Δ) obtained by transforming E. coli BL21 (DE3) strain with the expression vector pRSET-NS3Δ was genetically banked by the Korea Institute of Science and Technology. Was deposited in (Accession Number: KCTC 8779P).

(Step 4) Analysis of the nonstructural protein 3Δ gene of Korean hepatitis C virus

Expression

E. coli cells transformed in (step 3) were shaken for 12 hours in liquid Luria medium (6% bactotrypton, 0.5% yeast extract, 1% sodium chloride) containing 50 μg / ml of ampicillin. 5 ml of the culture was transferred to 500 ml of liquid Luria medium and shaken at 30 ° C., and IPTG was added so that the concentration was 1 mM in the culture when the absorbance of the culture was about 0.5 at 600 nm. After 3 hours of adding IPTG, E. coli cell precipitates were collected by centrifugation (Beckman J2-21 rotor; JA10) for 10 minutes at 6,000 rpm.

Example 2 Purification of Nonstructural Protein 3Δ of Korean Hepatitis C Virus

(Step 1) E. coli crushing

4 g of Escherichia coli obtained by culturing as described above were suspended in buffer 1 (20 mM sodium phosphate pH 7.6, 300 mM sodium chloride, 1 mM magnesium chloride, 10% glycerol, 0.1% Tween-20, 1 mM β-mercaptoethanol) and then ice bath Cells were disrupted by treatment at 50% power for 2 minutes using an ultrasonic grinder (Heat Systemas-Ultrasonics, Inc. W225, USA). The solution was centrifuged at 15,000 rpm for 30 minutes using a centrifuge (Beckman J2-21 rotor; JA20, USA), and the supernatant was taken and used for the next experiment.

(Step 2) Ni-chelating Histidine Affinity Gel Chromatography 1 ml of histidine-labeled affinity resin column in which the supernatant of (step 1) was previously equilibrated with buffer 1 of (step 1) (Invitrogen, USA), a nonstructural protein 3Δ having six histidines fused at the amino terminus was bound to the resin. Proteins that are weakly attached by nonspecific binding were washed with 10-20 ml of buffer 1 containing 5 mM, 20 mM, and 60 mM imidazole, respectively. The histidine-labeled protein was added to 10 ml of buffer 1 containing 1 M imidazole, and the fractions were collected by eluting the proteins adsorbed on the resin. The collected fractions were subjected to 15% SDS-polyacrylamide gel electrophoresis to select fractions containing nonstructural protein 3Δ and then collected. Then using a dialysis membrane (spectrum, USA) of mwco 8000 (molecular weight cut off 8000) 200 mM sodium phosphate pH 7.6, 50 mM sodium chloride, 1 mM magnesium chloride, 5 mM β-mercaptoethanol, 10% glycerol and 0.1% twin- Dialysis was performed in a buffer of 20 compositions.

Example 3 Western Blotting Using Polyclonal Antibody to Nonstructural Protein 3Δ

Purified nonstructural protein 3Δ was electrophoresed on 15% SDS-polyacrylamide gel, and then PVDF membrane was used for 1 hour at 200 mA using a semi-phor transfer kit (Semi-phor transfer kit, Hoffer Scientific Instrument, USA). Moved. The membrane was soaked in blocking solution (0.2% gelatin in phosphate buffer solution) and blocked for 1 hour. After washing the membrane with phosphate buffer solution, polyclonal antibody prepared by injecting hepatitis C virus non-structural protein 3 into rabbit was diluted with antibody (0.2% gelatin, 1% Triton × 100, 1mM EDTA, 0.02% T in phosphate buffer solution). Dilute 10,000 times in Murimesal and soak the membrane for 1 hour. After washing the membrane with phosphate buffer solution, anti-rabbit secondary antibody (Horse radish peroxidase; HRP) linked anti-rabbit secondary antibody (Gibco BRL, USA) was 3,000-fold in the antibody dilution solution. Soak in the diluted solution for 1 hour. The membrane was washed with phosphate buffer solution and developed in HRP color reaction solution (Bio-Rad. USA) to confirm the presence of nonstructural protein 3Δ.

The present invention allows mass production of only the protease active sites present in the non-structural protein 3 of the Korean hepatitis C virus in the form of an independent protein, and the histidine label is included therein so as to be easily isolated and purified by histidine-labeled affinity column chromatography. do.

Therefore, using the present invention, various protease proteins derived from hepatitis C virus can be used. Specifically, the enzyme can be used to easily select a proliferation inhibitor of hepatitis C virus, and ultimately develop a therapeutic agent such as hepatitis, cirrhosis and liver cancer caused by viral infection.

(Sequence list)

SEQ ID NO: 1

Sequence length: 27

Type of sequence: nucleic acid

Number of chains: 1 chain

Form: Straight

Type of sequence: Other nucleic acid (oligonucleotide)

[SEQ ID NO 1]

(Sequence list)

SEQ ID NO: 2

Sequence length: 28

Type of sequence: nucleic acid

Number of chains: 1 chain

Form: Straight

Type of sequence: Other nucleic acid (oligonucleotide)

[SEQ ID NO 2]

Claims (5)

A new protease protein derived from the nonstructural protein 3 of the Korean hepatitis C virus. The protease protein of claim 1, comprising a histidine label at the amino terminus. An expression vector pRSET-NS3Δ producing the protease protein of claim 2. E. coli transformants transformed with the expression vector pRSET-NS3Δ of claim 3 (Accession No .: KCTC 8779P). Inducing the expression of protease protein by culturing the E. coli transformant of claim 4 to obtain crude cell eluate therefrom to perform histidine-labeled affinity chromatography using an imidazole concentration gradient to obtain the protease protein of claim 1 Manufacturing method.