title: Functional definition of BirA suggests a biotin utilization pathway in the zoonotic pathogen Streptococcus suis.
abstract: Biotin protein ligase is universal in three domains of life. The paradigm version of BPL is the Escherichia coli BirA that is also a repressor for the biotin biosynthesis pathway. Streptococcus suis, a leading bacterial agent for swine diseases, seems to be an increasingly-important opportunistic human pathogen. Unlike the scenario in E. coli, S. suis lacks the de novo biotin biosynthesis pathway. In contrast, it retains a bioY, a biotin transporter-encoding gene, indicating an alternative survival strategy for S. suis to scavenge biotin from its inhabiting niche. Here we report functional definition of S. suis birA homologue. The in vivo functions of the birA paralogue with only 23.6% identity to the counterpart of E. coli, was judged by its ability to complement the conditional lethal mutants of E. coli birA. The recombinant BirA protein of S. suis was overexpressed in E. coli, purified to homogeneity and verified with MS. Both cellulose TLC and MALDI-TOFF-MS assays demonstrated that the S. suis BirA protein catalyzed the biotinylation reaction of its acceptor biotin carboxyl carrier protein. EMSA assays confirmed binding of the bioY gene to the S. suis BirA. The data defined the first example of the bifunctional BirA ligase/repressor in Streptococcus.
authors.affiliation: College of Life Science and Technology, Guangxi University, Nanning City, Guangxi 530004, China.|Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.
authors.forename: Huiyan
authors.initials: H
authors.lastname: Ye
authors.affiliation: Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.
authors.forename: Mingzhu
authors.initials: M
authors.lastname: Cai
authors.affiliation: Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.
authors.forename: Huimin
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.
authors.forename: Zhencui
authors.initials: Z
authors.lastname: Li
authors.affiliation: College of Life Science and Technology, Guangxi University, Nanning City, Guangxi 530004, China.
authors.forename: Ronghui
authors.initials: R
authors.lastname: Wen
authors.affiliation: Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.
authors.forename: Youjun
authors.initials: Y
authors.lastname: Feng
mesh_terms: D000103:Acetyl-CoA Carboxylase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D001710:Biotin / Q000378:metabolism*; D019731:Carbon-Nitrogen Ligases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development; D054889:Fatty Acid Synthase, Type II / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D021381:Protein Transport; D011994:Recombinant Proteins / Q000378:metabolism; D017011:Streptococcus suis / Q000201:enzymology* / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D011994:Recombinant Proteins; D001710:Biotin; D054889:Fatty Acid Synthase, Type II; D019731:Carbon-Nitrogen Ligases; D000103:Acetyl-CoA Carboxylase; C079633:biotin carboxyl carrier protein