title: Deciphering a unique biotin scavenging pathway with redundant genes in the probiotic bacterium Lactococcus lactis.
abstract: Biotin protein ligase (BPL) is widespread in the three domains of the life. The paradigm BPL is the Escherichia coli BirA protein, which also functions as a repressor for the biotin biosynthesis pathway. Here we report that Lactococcus lactis possesses two different orthologues of birA (birA1_LL and birA2_LL). Unlike the scenario in E. coli, L. lactis appears to be auxotrophic for biotin in that it lacks a full biotin biosynthesis pathway. In contrast, it retains two biotin transporter-encoding genes (bioY1_LL and bioY2_LL), suggesting the use of a scavenging strategy to obtain biotin from the environment. The in vivo function of the two L. lactis birA genes was judged by their abilities to complement the conditional lethal E. coli birA mutant. Thin-layer chromatography and mass spectroscopy assays demonstrated that these two recombinant BirA proteins catalyze the biotinylation reaction of the acceptor biotin carboxyl carrier protein (BCCP), through the expected biotinoyl-AMP intermediate. Gel shift assays were used to characterize bioY1_LL and BirA1_LL. We also determined the ability to uptake (3)H-biotin by L. lactis. Taken together, our results deciphered a unique biotin scavenging pathway with redundant genes present in the probiotic bacterium L. lactis.
authors.affiliation: Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, PR China.|Institute for Genomic Biology, University of Illinois, Urbana, Illinois 61801, USA.
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, PR China.
authors.forename: Qingjing
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Department of Microbiology, Southern Illinois University, Carbondale, IL 62901, USA.
authors.forename: Derek J
authors.initials: DJ
authors.lastname: Fisher
authors.affiliation: Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, PR China.
authors.forename: Mingzhu
authors.initials: M
authors.lastname: Cai
authors.affiliation: Department of Microbiology, University of Illinois, Urbana, IL 61801, USA.
authors.forename: Vandana
authors.initials: V
authors.lastname: Chakravartty
authors.affiliation: Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, PR 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, PR China.
authors.forename: Ping
authors.initials: P
authors.lastname: Li
authors.affiliation: Institute for Genomic Biology, University of Illinois, Urbana, Illinois 61801, USA.
authors.forename: Jose O
authors.initials: JO
authors.lastname: Solbiati
authors.affiliation: Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, PR China.
authors.forename: Youjun
authors.initials: Y
authors.lastname: Feng
mesh_terms: D000103:Acetyl-CoA Carboxylase / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D001710:Biotin / Q000378:metabolism*; D019921:Biotinylation; D019731:Carbon-Nitrogen Ligases / Q000235:genetics / Q000378:metabolism; D054889:Fatty Acid Synthase, Type II / Q000235:genetics / Q000378:metabolism; D013294:Lactococcus lactis / Q000235:genetics* / Q000378:metabolism*; D008958:Models, Molecular; D019936:Probiotics / Q000378:metabolism*; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid
chemical_list: D001426:Bacterial Proteins; D001710:Biotin; D054889:Fatty Acid Synthase, Type II; D019731:Carbon-Nitrogen Ligases; D000103:Acetyl-CoA Carboxylase; C079633:biotin carboxyl carrier protein