Polypeptide with anti-
A polypeptide with an anti- Mycobacterium tuberculosis activity, and a preparation method and use thereof are provided. The preparation method of the polypeptide includes the following steps: (1) preparing a straight-chain polypeptide with a sequence shown in SEQ ID NO: 1; and (2) allowing sulfhydryl groups of two cysteine residues in the straight-chain polypeptide to undergo a dehydration-condensation reaction with dimethylolurea to obtain the polypeptide. The polypeptide has little cytotoxicity and a prominent anti- Mycobacterium tuberculosis effect.
1. A polypeptide with an anti- Mycobacterium tuberculosis activity and having the sequence according to SEQ ID NO: 3, wherein the SEQ ID NO: 3 has a structural formula of the polypeptide as follows:
2. A method of preparing the polypeptide according to claim 1 , comprising the following steps:
(1) synthesizing a straight-chain polypeptide according to SEQ ID NO: 1 by Fmoc solid-phase coupling; and
(2) dissolving the straight-chain polypeptide and dimethylolurea in a solvent separately, and then mixing to allow sulfhydryl groups of two cysteine residues in the straight-chain polypeptide to undergo a dehydration-condensation reaction with dimethylolurea to obtain the polypeptide.
3. The method according to claim 2 , wherein a molar ratio of the straight-chain polypeptide to the dimethylolurea is 1:8 to 1:12.
4. The method according to claim 3 , wherein the solvent for the straight-chain polypeptide is one of a mixed solution of trifluoroacetic acid (TFA) and guanidine hydrochloride, an aqueous urea solution, acetonitrile, and phosphate buffered saline (PBS); and the solvent for the dimethylolurea is one of water, the acetonitrile, methanol, and N,N-dimethylformamide (DMF).
5. The method according to claim 4 , wherein a concentration of the aqueous urea solution is 4 mol/L to 8 mol/L.
6. The method according to claim 5 , wherein a concentration of the straight-chain polypeptide in the solvent for the straight-chain polypeptide is 1 mmol/L to 8 mmol/L, and a concentration of the dimethylolurea in the solvent for the dimethylolurea is 18 mmol/L to 80 mmol/L.
7. The method according to claim 6 , the method comprising adding an acid reaction regulator to the dehydration-condensation reaction in the step (2); the acid reaction regulator is a TFA; and a volume ratio of a solution of the straight-chain polypeptide to the acid reaction regulator is 1:1 to 1:3.
8. The method according to claim 7 , the method comprising conducting the dehydration-condensation reaction in the step (2) at 0° C. to 40° C. for 0 min to 10 min.
9. An anti- Mycobacterium tuberculosis drug in aqueous form comprising the polypeptide according to claim 1 .