ABSTRACT
Objective The specific binding peptide of Mycobacterium tuberculosis PPE17 protein was screened by phage display technique. Methods PPE17 gene was amplified from Mycobacterium tuberculosis genome, cloned into pET28a, expressed in E. coli BL21, purified by Ni2+ column, and identified by SDS-PAGE and Western blot. The purified PPE17 protein was coated into an ELISA plate and screened by phage 7 peptide library. After three rounds of panning, phage plaques were randomly selected for sequencing. DNAMAN was used to analyze and compare the amino acid sequences of the polypeptide encoded by the positive clones. Results PPE17 gene was successfully constructed and expressed, and soluble protein with molecular weight of about 37kD was obtained. From the third round of eluents, 20 plaque were randomly selected. The sequencing results could be translated into 8 polypeptide molecules, among which the polypeptide sequence repeated for 6 times was LKWGHVY. Conclusion The specific binding peptide of PPE17 protein is screened by phage display technology, which is expected to be a small molecular diagnostic reagent for the identification of this antigen.