Open AccessFunctional definition of BirA suggests a biotin utilization pathway in the zoonotic pathogen Streptococcus suis
Author(s) -
Huiyan Ye,
Mingzhu Cai,
Huimin Zhang,
Zhencui Li,
Ronghui Wen,
Youjun Feng
Publication year - 2016
Publication title -
scientific reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.24
H-Index - 213
ISSN - 2045-2322
DOI - 10.1038/srep26479
Subject(s) - streptococcus suis , biotin , pathogen , microbiology and biotechnology , biology , computational biology , genetics , gene , virulence
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 .