antimicrobial activity and molecular mechanism of the cres protein抗菌活性和分子机制的不尽的蛋白质.pdf
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Antimicrobial Activity and Molecular Mechanism of the
CRES Protein
Li Wang1,2., Qing Yuan1,2., Sunhong Chen1,2, Heng Cai1,2, Meige Lu1,2, Yue Liu1,2, Chen Xu1,2*
1 Department of Histology and Embryology, Shanghai Jiaotong University School of Medicine, Shanghai, China, 2 Shanghai Key Laboratory of Reproductive Medicine,
Shanghai, China
Abstract
Cystatin-related epididymal spermatogenic (CRES) protein, a member of the cystatin superfamily of cysteine protease
inhibitors (also known as CST8), exhibits highly specific, age-dependent expression in mouse testis and epididymis. The
CRES protein possesses four highly conserved cysteine residues which govern the overall conformation of the cystatins
through the formation of two disulfide bonds. Previous studies have revealed that other cystatin family members, such as
cystatin 3 and cystatin 11, show antibacterial activity in vitro. This prompted us to investigate the potential antimicrobial
activity of the CRES protein. Colony forming assays and spectrophotometry were used to investigate the effects of
recombinant CRES protein on Escherichia coli (E. coli) and Ureaplasma urealyticum (Uu), respectively, in vitro. After incubation
of E. coli with CRES recombinant protein fused with glutathione-S-transferase (GST), a substantial decrease in colony forming
units was observed, and the effect was dose and time dependent. Furthermore, it took longer for Uu to grow to plateau
stage when incubated with GST-CRES recombinant protein compared with the control GST. The antibacterial and Anti-Uu
activities were not impaired when the cysteine residues of CRES protein were mutated, indicating that the antimicrobial
effect was not dependent on its disulfide bonds. Functional analysis of three CRES polypeptides showed that the N-terminal
30 residues (N30) had no antimicrob
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