title: The Chlamydia trachomatis CT149 protein exhibits esterase activity in vitro and catalyzes cholesteryl ester hydrolysis when expressed in HeLa cells.
abstract: Chlamydia, like other intracellular bacteria, are auxotrophic for a variety of essential metabolites and obtain cholesterol and fatty acids from their eukaryotic host cell, however not many Chlamydia-specific enzymes have been identified that are involved in lipid metabolism. In silico analysis of one candidate Chlamydia trachomatis enzyme, annotated as a conserved putative hydrolase (CT149), identified two lipase/esterase GXSXG motifs, and a potential cholesterol recognition/interaction amino acid consensus (CRAC) sequence. His-tag purified recombinant CT149 exhibited ester hydrolysis activity in a nitrophenyl acetate-based cell-free assay system. When cholesteryl linoleate was used as substrate, ester hydrolysis occurred and production of cholesterol was detected by high performance liquid chromatography. Exogenous expression of transfected CT149 in HeLa cells resulted in a significant decrease of cytoplasmic cholesteryl esters within 48 h. These results demonstrate that CT149 has cholesterol esterase activity and is likely to contribute to the hydrolysis of eukaryotic cholesteryl esters during intracellular chlamydial growth.
authors.affiliation: Department of Microbiology, Immunology & Biochemistry, University of Tennessee Health Science Center, 901 Monroe Ave, Memphis, TN 38163, USA.
authors.forename: Jan
authors.initials: J
authors.lastname: Peters
authors.forename: Vijaya
authors.initials: V
authors.lastname: Onguri
authors.forename: Satoru K
authors.initials: SK
authors.lastname: Nishimoto
authors.forename: Tony N
authors.initials: TN
authors.lastname: Marion
authors.forename: Gerald I
authors.initials: GI
authors.lastname: Byrne
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology*; D002690:Chlamydia Infections / Q000382:microbiology*; D002692:Chlamydia trachomatis / Q000201:enzymology* / Q000235:genetics / Q000276:immunology; D002784:Cholesterol / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D002788:Cholesterol Esters / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism; D005260:Female; D006367:HeLa Cells; D006801:Humans; D006868:Hydrolysis; D007700:Kinetics; D051379:Mice; D008807:Mice, Inbred BALB C; D011993:Recombinant Fusion Proteins; D016415:Sequence Alignment; D002787:Sterol Esterase / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D000907:Antibodies, Bacterial; D002788:Cholesterol Esters; D011993:Recombinant Fusion Proteins; C021976:cholesteryl linoleate; D002784:Cholesterol; D002787:Sterol Esterase