title: Chlamydia trachomatis serovar L2 can utilize exogenous lipoic acid through the action of the lipoic acid ligase LplA1.
abstract: Lipoic acid is an essential protein bound cofactor that is vital for the functioning of several important enzymes involved in central metabolism. Genomes of all sequenced chlamydiae show the presence of two genes encoding lipoic acid ligases and one gene encoding a lipoate synthase. However, the roles of these proteins in lipoic acid utilization or biosynthesis have not yet been characterized. The two distinct lipoic acid ligases in Chlamydia trachomatis serovar L2, LplA1(Ct) and LplA2(Ct) (encoded by the open reading frames ctl0537 and ctl0761) display moderate identity with Escherichia coli LplA (30 and 27%, respectively) but possess amino acid sequence motifs that are well conserved among all lipoyl protein ligases. The putative lipoic acid synthase LipA(Ct), encoded by ctl0815, is ca. 43% identical to the E. coli LipA homolog. We demonstrate here the presence of lipoylated proteins in C. trachomatis serovar L2 and show that the lipoic acid ligase LplA1(Ct) is capable of utilizing exogenous lipoic acid for the lipoylation Therefore, host-derived lipoic acid may be important for intracellular growth and development. Based on genetic complementation in a surrogate host, our study also suggests that the C. trachomatis serovar L2 LipA homolog may not be functional in vivo.
authors.affiliation: Department of Microbiology and Immunology, F. Edward Hérbert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814-4799, USA.
authors.forename: Aishwarya V
authors.initials: AV
authors.lastname: Ramaswamy
authors.forename: Anthony T
authors.initials: AT
authors.lastname: Maurelli
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D002692:Chlamydia trachomatis / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology; D005816:Genetic Complementation Test; D008025:Ligases / Q000378:metabolism*; D008074:Lipoproteins / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D008063:Thioctic Acid / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D008074:Lipoproteins; D008565:Membrane Proteins; C089935:lplA protein, bacteria; D008063:Thioctic Acid; D008025:Ligases