TW200520771A - Antimicrobial peptides with reduced hemolysis and methods of their use - Google Patents

Abstract

The invention is directed to antimicrobial peptides related to cyclic and short peptides (less than 10 amino acid residues) with unique patterns of aromatic and cationic residues that perform a wide range of antimicrobial activities but display low hemolysis.

Description

200520771 (1) Description of the invention: 1. Field of the invention to which the invention belongs The invention is an antibacterial peptide. The main design feature is that it has a cyclic structure and consists of only 9 benzene rings and positively charged amino acids. Short peptide with excellent antibacterial ability. Compared to other long peptides, which also consist of a benzene ring and a positively charged amino acid, this extra tight short peptide exhibits excellent potency and low hemolysis. 2. Prior Art Background of the Invention The emergence of drug-resistant strains against traditional antibiotics has led to the search for new therapeutic agents, including many antimicrobial peptides of animal origin. At present, these antibacterial peptides have been found to play a very important role in the defense mechanisms of some hosts and larvae, including plants, insects, amphibians and mammals; and may have antibiotic activity against bacteria and fungi. Even some viruses. It binds to lipids (greater than ninety-five percent) and rapidly separates the lipid bilayer, destroying membrane integrity. On the other hand, it is also possible to increase small and short-term conduction on the flat lipid bilayer of the bacteria, so that the cell plasma membrane is partially depolarized and the original potential gradient is destroyed. The protective function of such antibacterial peptides in host defense has been proven in fruit fly experiments; when the fruit fly is infected with microorganisms, if the expression of antibacterial peptides decreases, shellfish (1 will greatly reduce its survival rate. In In mammals, its function can also be confirmed by defective bacterial killing of patients with pulmonary cystic fibrosis and mice. The antibacterial peptides found in mammals can be classified as cysteine-rich Defensins (α, β defensins) and a variety of cathelicidin. Cathelicidin contains a highly retained signal sequence and anterior region (cathdin "cathdin" ) And the mutated antibacterial sequence shell [J is located in the C-terminal block. Many cathelicidins contain between the negatively-charged cathlin block and the positively-charged C-terminal block. Unique elastin enzyme cleavage site; proteolytic reaction at this site has been observed in bovine or pig neutrophils and is necessary for antibacterial activity. According to the amino acid composition and structure, this card color Lixidine ( The cathelicidin) family can be further classified into three groups. The first group of α-helical peptides with hydrophilic lipids, such as LL-37, 200520771 CRAMP, SMAP-29, PMAP-37, BMAP-27 and BMAP-28; The second class of beta is rich in arginine or tryptophan peptides, such as Bac5, Bac7, PR-39, and indolicidin; the third group is cysteine-containing peptides, For example, protegrins 〇Because antibacterial peptides usually have low molecular weight "5 kDa", a wide range of activities, and constitute an important part of the host's defense system against microbial infections, it can be used as a starting point for the design of low molecular weight antibacterial point. Furthermore, because it has both hydrophobic and charged regions, it has the potential to fold into a hydrophilic lipid structure. This property is also related to its ability to hydrolyze the cell plasma membrane. However, despite their broad antibacterial efficacy, these peptides have different hemolytic activities against red blood cells, which greatly limits the potential for treatment. The main purpose of this test is to design peptides with activity against clinically important strains and to understand some important characteristics of peptide structure by modifying the primary and secondary structure. Our results show that with the modification of the primary or secondary structure, the activity or toxicity of 2Nvsun's natural antibacterial peptides is feasible. This invention relates to antibiotics, and is considered to be a new type of antimicrobial peptide-tryptophan-rich sequence ', which has a wide range of uses, and has both antibacterial activity and low hemolytic properties. In short, the present invention is an antibiotic designed directly against a broad range of Gram-positive, negative bacteria, protozoa, fungi, and enveloped human autoimmune-deficiency virus. III. SUMMARY OF THE INVENTION The invention described here is mainly designed for cyclic, short peptides, which has both improved serum compatibility and reduced hemolysis. Furthermore, the peptides of this invention also show a wide range of Antibacterial activity, including Gram-positive, negative bacteria, and multidrug-resistant pathogens. This antimicrobial peptide contains less than 10 amino acids, the sequence is:

(AlXlA2) N wherein A is selected from arginine (Arg), lysine (Lys), valine (Val) and isoleucine (lie); X is selected from tryptophan (Trp), amphetamine Acid (Phe), A2 is selected from arginine (Arg), lysine (Lys), valine (Val) and isoleucine (lie;) 200520771 N is 1, 2 Or 3, the configuration is cyclic or linear. The present invention has several characteristics: first, the peptide has less than 10 amino acids, and the configuration is very tight, so it can efficiently pass through the cell membrane; Second, the best peptides obtained by the present invention can widely resist already resistant strains and medically important fungi. In addition, these peptides have the ability to resist endotoxin and can be used with traditional antibiotics. The most important Yes, this invention improves the compatibility of serum, and has very low hemolysis for human red blood cells compared to natural protegrins and indolicidin analogs. Details of the invention Describes tryptophan-rich peptides as described in U.S. Patent Nos. 6,303,575, 6,180,604, 5,821,224, 5,547,939, 5,459,325, and 5,324,716 All naturally occurring peptides have more than 10 amino acid sequences and are rapidly broken down in the body. Indolicidin analogs usually have the amino acid sequence of ILPWKWPWWPWX, X represents 1 or 2 selected amino acids (U.S. Patent No. 5,547,939). These previous descriptions of tryptophan-rich peptides are different from the invention described in this article, and our antibacterial peptides are designed to have broad antibacterial properties directly Cyclic short peptides (less than 10 amino acids) and have improved selectivity and low hemolysis. Cyclized linear antibacterial peptides have several advantages for their selectivity and stability, such as ... (1) Unfolded peptides will form precipitates due to the action of water repellency, resulting in non-specific absorption into normal mammalian cells and low solubility. If the unfolded configuration is restricted and its repellency is limited Exposure to aqueous amino acids can limit this water repellent interaction. Furthermore, these constraints can increase the role of electrostatic forces in the initial binding of peptides to negatively charged membranes; so In fact, it increases the selectivity of peptides to bacterial or mammalian cells. (2) Since the action of proteolytic enzymes requires the extension of the peptide structure and exposes the cleavage site, the cyclized short peptide may be used to The strong and bound structure limits its sensitivity to proteolytic enzymes. (3) Because cyclization seems to only affect its activity against Gram-negative bacteria, more research on this may help The peptide can be designed for the solubilization of specific bacteria. The peptide of this invention can be expressed in the following form: (AiXiA2) n A is selected from Arginine, Lysine, Valine ( Val) and isoleucine (Ik); 200520771 X is selected from tryptophan (Tip), phenylalanine (Phe) and proline (Pro); A2 is selected from arginine (Arg), lysine (Lys), valine (Val) and isoleucine (lie); N is 1, 2 or 3; its configuration is cyclic or linear. The following are some examples of antibacterial peptides of the invention: cyclic-Lys Phe He, linear-LysPhelle, cyclic-Arg Phe He, linear-Arg Phe lie, cyclic-Arg Phe Va, linear-Arg Phe Val, cyclic, Lys Phe Arg, linear-Lys Phe Arg, cyclic-LysTrpVa, linear-Lys Trp Val, cyclic-Lys Trp lie, linear-Lys Trp lie, cyclic-Lys Trp Arg, Straight Dog-Lys Trp Arg, Cyclic-Arg Trp Va Straight Chain-Arg Trp Va Circular-Lys Trp Arg Arg Trp lie, Linear-Lys Trp Arg Arg Trp lie, Cyclic _ Lys Trp Arg Arg T卬 Vabu Linear-Lys Trp Arg Arg Trp Val, Cyclic-Lys Trp lie Lys Trp Arg, 200520771 Linear-Lys Trp lie Lys Trp Arg, Cyclic_Lys Trp Val Lys Trp lie, Linear_Lys Trp Val Lys Trp lie, cyclic-Lys Trp lie Lys Trp lie, linear-Lys Trp lie Lys Trp lie, cyclic-Lys Trp lie Lys Trp lie Lys Trp lie, linear-Lys Trp lie Lys Trp lie Lys Trp lie, cyclic-Lys Phe lie Lys Phe lie Lys Phe lie, linear-Lys Phe lie Lys Phe lie Lys Phe lie, cyclic-Lys Trp Arg Arg Trp Val Arg Trp lie, linear-Lys Trp Arg Arg Trp Val Arg Trp lie, cyclic-lie Trp Arg Val Trp Arg Arg Trp Lys, linear-lie Trp Arg Val Tip Arg Arg Trp Lys, cyclic-Lys Phe Arg Arg Phe Val Arg Phe He, linear-Lys Phe Arg Arg Phe Val Arg Phe lie, cyclic-Lys Pro Arg Arg Pro Val Arg Pro lie, linear-Lys Pro Arg Arg Pro Val Arg Pro lie, Cyclic-Lys Trp lie Arg Trp Val Arg Trp lie, and linear-Lys Trp lie Arg Trp Val Arg Trp lie IV. Implementation Examples Example 1: Peptide Verification 'Synthesis' Purification and characteristics of peptides are similar The substances and their names are shown in Table 1 below. Each amino acid is represented by three letters instead. 200520771 Table, Name Amino Acid Sequence Number Pac-301 C Lys Trp Arg Arg Trp lie SEQIDN〇: 1 Pac-301 L Lys Trp Arg Arg Trp lie SEQIDN〇: 1 Pac-302 C Lys Trp Arg Arg Trp Val SEQIDNO: 2 Pac-302 L Lys Trp Arg Arg Trp Val SEQIDNO: 2 Pac-303 C Lys Trp lie Lys Trp Arg SEQIDN〇: 3 Pac-303 L Lys Trp lie Lys Trp Arg SEQIDN〇: 3 Pac-304 C Lys Trp Val Lys Trp lie SEQIDNO: 4 Pac-304 L Lys Trp Val Lys Trp lie SEQ ID NO: 4 Pac-305 C Lys Trp lie Lys Trp lie SEQIDN〇: 5 Pac-305 L Lys Trp lie Lys Trp lie SEQ ID N〇: 5 Pac-521 C Lys Trp lie Lys Trp lie Lys Trp lie SEQIDN〇: 6 Pac-521 L Lys Trp lie Lys Trp lie Lys Trp lie SEQIDNO: 6 Pac-522 C Lys Phe lie Lys Phe lie Lys Phe lie SEQIDNO: 7 Pac-522L Lys Phe lie Lys Phe lie Lys Phe lie SEQIDN〇: 7 Pac-525 C Lys Trp Arg Arg Trp Val Arg Trp lie SEQIDN〇: 8 Pac-525 L Lys Trp Arg Arg Trp Val Arg Trp lie SEQ ID NO: 8 Pac-526 C He Trp Arg Val Trp Arg Arg Trp Lys SEQ ID NO: 9 Pac-526 L He Trp Arg Val Trp Arg Arg Trp Lys SEQ ID NO: 9 Pac-527 CL ys Phe Arg Arg Phe Val Arg Phe lie SEQ ID NO: 10 Pac-527 L Lys Phe Arg Arg Phe Val Arg Phe He SEQ ID NO: 10 Pac-528 C Lys Pro Arg Arg Pro Val Arg Pro lie SEQ ID NO: 11 Pac-528 L Lys Pro Arg Arg Pro Val Arg Pro He SEQ ID NO: 11 Pac-529 C Lys Trp lie Arg Trp Val Arg Trp lie SEQIDNO: 12 Pac-529 L Lys Trp lie Arg Trp Val Arg Trp lie SEQ ID NO : 12

C: cyclic; L: linear 10 200520771 All linear peptides are synthesized by solid-state synthesis, using standard Fmoc: (N- (9-fluorenyl) methoxycarbonyl) chemical synthesis in PAL resin (5- (4-Fmoc-aminomethyl-3,5-dimethoxyphenoxy) -valeric acid-methylaniline resin); and the Fmoc protecting group on these resins is 20% hexahydro Pyridine / DMF was removed and the reaction time was about 1 to 1.5 hours, after which it was determined with water and a ninhydrin test. Next, 95% trifluoroacetic acid (TFA) was added and mixed for 1 to 1.5 hours, and the unprocessed peptide was cut from the resin; and then purified by reverse-phase high-pressure liquid chromatography. The reverse-phase high-pressure liquid chromatography used here is a semi-preparative C18 reverse-phase column. The purified mobile phase was mixed with acetonitrile and water in different ratios (the procedure is shown in Table 1); the wavelength was detected at 225 and 280 nm; the flow rate was 4 ml / min. The obtained main peptide product was then determined by fast atom bombard mass spectrophotometry (FAB-MS) to determine the molecular weight. The purity of each peptide was determined by a reverse-phase high-pressure liquid chromatography column. Example 2: In vitro victory surface In general, the antibacterial activity of in vitro peptides can be tested using standard clinical laboratory standard National Committee (NCCLS) bacterial inhibition assays or minimum inhibitory concentration (MIC). The so-called minimum inhibitory concentration refers to the minimum peptide concentration required to inhibit or reduce the growth of a test organism. The organisms tested by the minimum inhibitory concentration analysis method are shown in Table 2:

11 200520771 BacUlussubstiUs (Staphylococcusaureus ^) from Staphylococcus aureus i Staphylococcus epidermidis (5 bodies such as / 〇% > 〇 ^) ) Bacillus {Bacilluspumilus, Ceratocystis (and c / Galana) {Pseudomonasaeruginosa) {Staphylococcusaureus) E. coli (5) ATCC 6633 ATCC 9144 ATCC 12228 ATCC 29737 ATCC 14884 ATCC 11778 ATCC 27853 ATCC 29213 ATCC 25922

To put it simply, the bacterial solution cultured overnight was diluted with Meuller-Hinton growth medium to an inoculum containing approximately 105 colonies; the peptide was also serially diluted twice, and the diluted bacteria were added. In the liquid. After 18 hours incubation at 37 ° C, the turbidity was analyzed; the minimum inhibitory concentration of each peptide was measured three times at different times, and the average radon was calculated, as shown in Table III, Figure 1 and Figure 2. Based on these results, we found that Pac521-530 has the largest antibacterial activity against Gram-negative and positive bacteria. Furthermore, pac-521 ~ 530 also exhibited a larger φ antibacterial activity than Pac-301 ~ 310. 12 200520771 Table 3. Minimum inhibitory concentrations of synthetic peptides on E. coli and S. aureus (μ§M) Name E. coli S. aureus Pac_301 C > 64 Pac-301 L > 64 16 8 Pac-303 C > 64 > 64 Pac-303 L 24 16 Pac-305 C > 64 > 64 Pac-305 L 24 16 Pac-521 C 64 64 Pac-521 L 8 16 Pac-522 C 64 64 Pac-522 L 8 4 Pac-525 C 64 64 Pac-525 L 2 4 Pac-526 C 64 64 Pac-526L 4 4 Pac-527 C 64 64 Pac-527 L 4 4 Pac-528 C 64 64 Pac-528 L 2 4 Pac-529 C 64 64 Pac-529 L 8 4 C: cyclic; L: linear

13 200520771 Table 4. Minimum inhibitory concentrations of peptides synthesized by organisms (MIC " g / ml) Phosphate-free buffer IX Phosphate buffer Pac-525 L Pac-527 L Pac-525 L Pac-527 L Bacillus subtilis 4 4 4 2 Staphylococcus epidermidis 2 2 2 4 Staphylococcus aureus 4 4 8 4 Bacillus 4 2 8 4 Lactobacillus 2 4 8 4 Pseudomonas aeruginosa 2 4 4 8 Escherichia coli 2 4 8 8 Example 3: Analysis of membrane penetration The outer membrane penetration of the peptide was determined by the absorption test of 1-iV-bennaphthylamine (NPN). Intact E. coli cells NPN shows weak fluorescence absorption in a liquid environment, and strong absorption in a water-repellent environment, so it indicates that NPN is water-repellent and can be used to directly measure the degree of outer membrane penetration. Under normal circumstances, E. coli absorbs little or even no NPN; in the presence of some membrane penetrating compounds (ethylenediaminetetraacetic acid, polymyxin B), neomycin Or antibacterial), NPN will partially penetrate the outer membrane of bacteria and increase the fluorescence absorption. The experimental procedure is briefly described as follows: 1 ml of the overnight bacterial culture was added to 50 ml of the culture medium, and cultured at 37 ° C with shaking to an OD600 equal to 0.4 to 0.6, and the cells were detached at 3500 rpm for 10 minutes. Rinse and resuspend the centrifuged cells to ODf 0.5 with buffer. Pipette 1 ml into a clear cuvette and measure for 2 to 5 seconds. Add 0.5 millimoles of NPN 20 microliters, mix well and measure for 2 ~ 5 seconds. Then add 10 microliters of 100 times antibiotics, mix well, and measure until the maximum value is reached (5 minutes). Therefore, the fluorescence absorption 値 changes with the concentration of peptides, and the concentration of peptides required to reach 50% of the maximum increase in NPN is defined as P5. ° Indeed, the experimental results show that all peptides have the ability to bind to the membrane under the NPN absorption test. The data are shown in Table 5 and Figure 2. Table 5: Ability to penetrate the outer membrane of E. coli and promote NPN uptake _ _ __ _ _ win p50te / ml) Pac 301 L 8 Pac 305 L 16 Pac 309 L 8 Pac 521 L 2 Pac 525 L 2 Pac 529 L 4

Example 4: Characteristics of tryptophan environment Due to the sensitivity of tryptophan to the degree of polarization of the surrounding environment, it is often used as a study to measure polarization or binding. We used the LS-55 spectrofluorimeter [Perkin-Elmei: company] to complete fluorescence scattering spectra at 300 and 450 nanometers in 25 5mm quartz cells; the excitation wavelength was set to 280 Nanometers; both the scattering and excitation gate widths are 5 nanometers. In the case of phosphate buffer, this series of antimicrobial peptides has the largest scattering at a wavelength of 357 nm; while in the presence of sodium dodecyl sulfate (SDS), the maximum scattering wavelength shifts to blue (blue shifted) By 8 nanometers, the intensity also increased. This result shows that the branches of the excellent amino acid are moved to a more water-repellent environment, and the result is shown in FIG. 3. Example 5 · The secondary structure CD spectrum of the peptide of the lion tf detected by optical dispersion spectrum (CD) was obtained from an AVIV 62DS spectropolarometer after correction by J-10-carbonphorsulfonic acid; use Transparent small test tube with a light diameter of 1 mm. The experimental conditions were 30 micromolar of peptide concentration in a sodium phosphate buffer at a pH of 7.2 and a concentration of 10 millimolar. The far-ultraviolet spectrum with a wavelength of 190-260 nm was collected with a step size of 0.5 nm and an average time of one second. In the absence of phospholipids, Pac-301 ~ 310 and Pac-521 ~ 530 did not show the characteristics of regular structure (Table 6); however, after the SDS was added, the structure 15 200520771 was induced (Figure 4) ). Table hexapeptide structure in phosphate buffer structure in sodium dodecyl sulfate Pac-301 C random structure Pac-301 L random structure a little regular structure Pac-305 C random structure irregular structure Pac- 305 L Irregular structure Pac-522 C Irregular structure Pac-522 C Irregular structure Pac-522 C Irregular structure Pac-525 C Irregular structure Pac-525 L Irregular structure Little regular structure Example 6 : Fermented cell lysate Pac-521 ~ 530 is used to test the blood cell solubility of human red blood cells. Erythrocytes with ethylenediaminetetraacetic acid were rinsed three times with phosphate buffered saline (PBSM800 & 10 minutes) and finally suspended in PBS; diluted to 10% and aliquoted in 50 microliter volumes per tube. Then the peptide dissolved in PBS buffer was added, and cultured at 37 ° C for one hour (final red blood cell concentration was 5% v / v); centrifuged at 800 ^ for 10 minutes. Pretreated red blood cells and peptides of different concentrations were cultured to obtain their hemolytic percentages. The results showed that Pac_525 had significantly lower hemolysis for red blood cells than other antimicrobial peptides (Table 7 and Figure 5). Table 7_ Peptide lysate at 5 μ2 / ιη1 concentration at 5 μg / ml concentration at 50 μg / ml concentration at 50 μg / ml concentration lysis percentage Pac-301 L 0.85 6.8 14 Pac- 305 L 0.74 7.2 15 Pac-524L 0.82 7.3 15 Pac-525 L 0.81 7.2 14 16 200520771 [Simplified illustration of the figure] Figure 1 shows the survival after treatment with Pac-525 (filled circle) and Pac-524 (open circle) Graph (A) Bacillus. Substilis ATCC6633; (Staphylococcus aureus) ATCC9144; (C) E. coli (5) ATCC25922; (D) Pseudomonas aeruginosa ) ATCC27853. Figure 2 is the measurement of Pac-525-induced adventitia permeability using NPN uptake analysis ((^ g / ml: solid square; 1μ2 / ιι ± hollow circle; 2pg / ml: hollow square; 3pg / m) (Open triangle). Figure 3 shows the use of tryptophan fluorescent light absorption to record the environmental changes induced by dodecyl sulfate sodium Pac-525. Figure 4 shows (A) Pac-525 and (B) Pac-526 CD spectrum in phosphate buffer (open circles) or 10 mM SDS (filled circles). Figure 5 shows that peptides have very low hemolysis to human red blood cells (filled circles: melittin ( melittin); hollow circle: Pac-525; solid triangle (Pac-527). 200520771 Sequence Listing < 110 > Applicant Names Zeng Xiuru & Cheng Jiawei < 120 > Low Hemolytic Antibiotic Peptide and Method of Use < 160 >; 12

< 210> 1 < 211 > 6 < 212 > PRT < 213> Artificial sequence < 220> < 223 > A linear or cyclic configuration peptide with antibacterial activity < 400 > 1

Lys Trp Arg Arg Trp lie 1 5 < 210 > 2 < 211 > 6 < 212 > PRT < 213 > Artificial sequence < 220 > < 223> Linear or cyclic configuration peptide with antibacterial activity 18 200520771 < 400 > 2

Lys Trp Arg Arg Trp Val 1 5 < 210 > 3 < 211 > 6 < 212 > PRT < 213> Artificial sequence

< 220 > < 223> A linear or cyclic configuration peptide having antibacterial activity < 400 > 3

Lys Trp lie Lys Trp Arg 1 5

< 210 > 4 < 211 > 6 < 212 > PRT < 213> Artificial sequence < 220 > < 223> Linear or cyclic configuration peptide with antibacterial activity < 400 > 4

Lys Trp Val Lys Trp lie 1 5 < 210 > 5 19 200520771 < 211 > 6 < 212 > PRT < 213> Artificial sequence < 220> < 223> Linear or cyclic configuration peptide having Antibacterial activity < 400 > 5

Lys Trp lie Lys Trp lie 1 5 < 210 > 6 < 211 > 9 < 212 > PRT < 213 > artificial sequence < 220>

< 223 > A linear or cyclic configuration peptide with antibacterial activity < 400 > 6

Lys Trp lie Lys Trp lie Lys Trp lie 1 5 < 210 > 7 < 211 > 9 < 212 > PRT < 213 > Artificial Sequence 20 < 220 > 200520771 < 223 > Linear or circular configuration wins Peptide with antibacterial activity < 400 > 7

Lys Phe lie Lys Phe lie Lys Phe lie 1 5

< 210 > 8 < 211 > 9 < 212 > PRT < 213〉 artificial sequence < 220> < 223> linear or cyclic configuration peptide with antibacterial activity < 400 > 8

Lys Trp Arg Arg Trp Val Arg Trp lie 1 5

< 210 > 9 < 211 > 9 < 212 > PRT < 213> Artificial sequence < 220 > < 223 > Linear or cyclic configuration peptide with antibacterial activity < 400 > 9 lie Trp Arg Val Trp Arg Arg Trp Lys 21 200520771 < 210〉 10 < 211 > 9 < 212 > PRT < 213 Recognition Sequence < 220>

< 223> A linear or cyclic configuration peptide having antibacterial activity < 400 > 10

Lys Phe Arg Arg Phe Val Arg Phe lie 1 5

< 210 > 11 < 211 > 9 < 212> PRT < 213> Artificial sequence < 220 > < 223 > A linear or cyclic configuration peptide with antibacterial activity < 400 > 11

Lys Pro Arg Arg Pro Val Arg Pro lie 1 5 < 210 > 12 22 200520771 < 211 > 9 < 212 > PRT < 213 > Artificial sequence < 220> < 223 > Linear or circular configuration wins Peptide with antibacterial activity < 400 > 12

Lys Trp lie Arg Trp Val Arg Trp lie 1 5

twenty three

Claims (1)

200520771 The scope of patent application: 1. A cyclic peptide with antibacterial activity, which has the chemical form as follows: (A) XiA2) n where 乂 is selected from arginine (Arg), lysine (Lys), Valine (Vai) and Isoleucine (Ile); Xi is selected from tryptophan (Tip), phenylalanine (Phe and proline) (Pro); A2 is selected from arginine (Arg), ion Nys (Lys), valine (Val) or isoleucine (Iie); N is 1, 2 or 3. 2. The cyclic peptide according to item 1 of the patent application scope, which is selected from the following sequences: (SEQIDN0: 1) (SEQIDNO: 2) (SEQIDN0: 3) (SEQIDNO: 4) (SEQIDN0: 5) Lys Trp Arg Arg Trp lie Lys Trp Arg Arg Trp Val Lys Trp lie Lys Trp Arg Lys Trp Val Lys Trp lie Lys Trp lie Lys Trp lie Lys Trp lie Lys Trp lie Lys Trp lie (SEQ ID N〇: 6), Lys Phe lie Lys Phe lie Lys Phe lie (SEQ ID NO: 7), Lys Trp Arg Arg Trp Val Arg Trp lie (SEQ ID NO: 8) ' He Trp Arg Val Trp Arg Arg Trp Lys (SEQ ID NO: 9) 'Lys Phe Arg Arg Phe Val Arg Phe lie (SEQ ID NO: 10), Lys Pro Arg Arg Pro Val Arg Pro lie (SEQ Π) NO: 11 ) And Lys Trp He Arg Trp Val Arg Trp lie (SEQ ID NO: 12) ° 3. For example, the cyclic peptide of the scope of patent application No. 2 is a linear or cyclic topological peptide. 4. The cyclic peptide according to item 3 of the patent application scope, which is a peptide which is aminated by a carbon terminal amino acid. 5. The cyclic peptide according to item 3 of the patent application scope, which is an acetylated peptide with a nitrogen terminal amino acid. 24 200520771 6. The cyclic peptide according to item 3 of the scope of patent application, which is a carbamate-terminated peptide. 7. The cyclic peptide according to item 3 of the patent application scope, which has more than one D-type amino acid. 8. A pharmaceutical composition having antibacterial activity, comprising a cyclic peptide selected from, for example, items 1 to 7 of the scope of patent application, and a carrier or excipient. 9. A method for deactivating endotoxin of a gram-negative bacterium, at least comprising administering to a subject in need thereof a therapeutically effective amount of a cyclic peptide selected from the range of claims 1 to 7 of the patent application. 10. A method of treating or preventing a bacterial or viral infection, comprising at least administering to a subject in need thereof a therapeutically effective amount of a ring-shaped victory selected from the range of claims 1 to 7 of the patent application. 11. A method for inhibiting the growth of microorganisms, comprising at least administering a therapeutically effective amount of a cyclic peptide selected from the range of claims 1 to 7 of the patent application. 25