title: The temperature activated HtrA protease from pathogen Chlamydia trachomatis acts as both a chaperone and protease at 37 degrees C.
abstract: Characterization of the protease, HtrA, from pathogen Chlamydia trachomatis is presented. The purified recombinant protein was a serine endoprotease, specific for unfolded proteins, and temperature activated above 34 degrees C. Chaperone activity was observed, although this appeared target-dependent. Inactive protease (S247A) was able to chaperone insulin B-chain, irrespective of temperature, but at 30 degrees C only HtrA and not S247A displayed significant chaperone activity for alpha-lactalbumin. These data demonstrate that chaperone activity may involve functional protease domain and that C. trachomatis HtrA functions as both a chaperone and protease at 37 degrees C. These properties are consistent with the developmental cycle of this obligate intracellular bacterium.
authors.affiliation: Institute of Health and Biomedical Innovation and School of Life Sciences, Faculty of Science, Queensland University of Technology, Brisbane, Australia.
authors.forename: Wilhelmina M
authors.initials: WM
authors.lastname: Huston
authors.forename: Joaquim E
authors.initials: JE
authors.lastname: Swedberg
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Harris
authors.forename: Terence P
authors.initials: TP
authors.lastname: Walsh
authors.forename: Sarah A
authors.initials: SA
authors.lastname: Mathews
authors.forename: Peter
authors.initials: P
authors.lastname: Timms
mesh_terms: D000595:Amino Acid Sequence; D002364:Caseins / Q000378:metabolism; D002692:Chlamydia trachomatis / Q000201:enzymology* / Q000235:genetics / Q000472:pathogenicity; D002942:Circular Dichroism; D004789:Enzyme Activation; D006360:Heat-Shock Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D007328:Insulin / Q000378:metabolism; D007768:Lactalbumin / Q000378:metabolism; D011485:Protein Binding; D017510:Protein Folding; D017433:Protein Structure, Secondary; D012694:Serine / Q000235:genetics / Q000378:metabolism; D012697:Serine Endopeptidases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D002364:Caseins; D006360:Heat-Shock Proteins; D007328:Insulin; D012694:Serine; D007768:Lactalbumin; D012697:Serine Endopeptidases