title: Structural basis for activation and inhibition of the secreted chlamydia protease CPAF.
abstract: The obligate intracellular pathogen Chlamydia trachomatis is the most common cause of sexually transmitted bacterial disease. It secretes a protease known as chlamydial protease/proteasome-like activity factor (CPAF) that degrades many host molecules and plays a major role in Chlamydia pathogenesis. Here, we show that mature CPAF is a homodimer of the catalytic domains, each of which comprises two distinct subunits. Dormancy of the CPAF zymogen is maintained by an internal inhibitory segment that binds the CPAF active site and blocks its homodimerization. CPAF activation is initiated by trans-autocatalytic cleavage, which induces homodimerization and conformational changes that assemble the catalytic triad. This assembly leads to two autocatalytic cleavages and removal of the inhibitory segment, enabling full CPAF activity. CPAF is covalently bound and inhibited by the proteasome inhibitor lactacystin. These results reveal the activation mechanism of the CPAF serine protease and suggest new opportunities for anti-Chlamydia drug development.
authors.affiliation: College of Biological Sciences, China Agricultural University, Beijing, China.
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: Huang
authors.forename: Yingcai
authors.initials: Y
authors.lastname: Feng
authors.forename: Ding
authors.initials: D
authors.lastname: Chen
authors.forename: Xiaojing
authors.initials: X
authors.lastname: Wu
authors.forename: Siyang
authors.initials: S
authors.lastname: Huang
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Wang
authors.forename: Xingguo
authors.initials: X
authors.lastname: Xiao
authors.forename: Wenhui
authors.initials: W
authors.lastname: Li
authors.forename: Niu
authors.initials: N
authors.lastname: Huang
authors.forename: Lichuan
authors.initials: L
authors.lastname: Gu
authors.forename: Guangming
authors.initials: G
authors.lastname: Zhong
authors.forename: Jijie
authors.initials: J
authors.lastname: Chai
mesh_terms: D000111:Acetylcysteine / Q000031:analogs & derivatives / Q000494:pharmacology; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism*; D002692:Chlamydia trachomatis / Q000201:enzymology*; D018360:Crystallography, X-Ray; D019281:Dimerization; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D008954:Models, Biological; D008958:Models, Molecular; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D021122:Protein Subunits; D012697:Serine Endopeptidases / Q000737:chemistry* / Q000378:metabolism*; D037521:Virulence Factors / Q000737:chemistry / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D004791:Enzyme Inhibitors; D021122:Protein Subunits; D037521:Virulence Factors; C067713:lactacystin; D012697:Serine Endopeptidases; D000111:Acetylcysteine