title: Evidence that TP_0144 of Treponema pallidum is a thiamine-binding protein.
abstract: Thiamine pyrophosphate (TPP), the biologically active form of thiamine (also known as vitamin B1), is an essential cofactor for several important enzymes involved in carbohydrate metabolism, and therefore, it is required for all living organisms. We recently found that a thiamine-binding protein (TDE_0143) is essential for the survival of Treponema denticola, an important bacterial pathogen that is associated with human periodontitis. In this report, we provide experimental evidence showing that TP_0144, a homolog of TDE_0143 from the syphilis spirochete Treponema pallidum, is a thiamine-binding protein that has biochemical features and functions that are similar to those of TDE_0143. First, structural modeling analysis reveal that both TDE_0143 and TP_0144 contain a conserved TPP-binding site and share similar structures to the thiamine-binding protein of Escherichia coli. Second, biochemical analysis shows that these two proteins bind to TPP with similar dissociation constant (Kd) values (TDE_0143, Kd of 36.50 nM; TP_0144, Kd of 32.62 nM). Finally, heterologous expression of TP_0144 in a ΔTDE_0143 strain, a previously constructed TDE_0143 mutant of T. denticola, fully restores its growth and TPP uptake when exogenous thiamine is limited. Collectively, these results indicate that TP_0144 is a thiamine-binding protein that is indispensable for T. pallidum to acquire exogenous thiamine, a key nutrient for bacterial survival. In addition, the studies shown in this report further underscore the feasibility of using T. denticola as a platform to study the biology and pathogenicity of T. pallidum and probably other uncultivable treponemal species as well.
authors.affiliation: Department of Oral Biology, State University of New York at Buffalo, Buffalo, New York, USA.
authors.forename: Jiang
authors.initials: J
authors.lastname: Bian
authors.affiliation: Department of Bioinformatics, School of Basic Medicine and Biological Sciences, Soochow University, Suzhou, People's Republic of China.
authors.forename: Youbin
authors.initials: Y
authors.lastname: Tu
authors.affiliation: Laboratory of Molecular Biology, Training Center of Medical Experiments, School of Basic Medical Sciences, Fudan University, Shanghai, People's Republic of China.
authors.forename: Song-Mei
authors.initials: SM
authors.lastname: Wang
authors.affiliation: Key Laboratory of Medical Molecular Virology of MOE/MOH and Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, People's Republic of China.
authors.forename: Xuan-Yi
authors.initials: XY
authors.lastname: Wang
authors.affiliation: Department of Oral Biology, State University of New York at Buffalo, Buffalo, New York, USA Department of Microbiology and Immunology, State University of New York at Buffalo, Buffalo, New York, USA cli9@buffalo.edu.
authors.forename: Chunhao
authors.initials: C
authors.lastname: Li
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology; D013831:Thiamine / Q000378:metabolism*; D014210:Treponema pallidum / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; C026989:thiamine-binding protein; D013831:Thiamine