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International Summer School
From Genome to Life:
Structural, Functional and Evolutionary approaches
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RODIONOV
Dimitry |
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State Scientific Center For Biotechnology Gosniigenetika, Bioinformatics, 1st Doroznyi Pr., 1, Moscow 113545, Russia title: Computational analysys of the biotin regulon in bacterial genomes Biotin is a
necessary co-factor of numerous biotin-dependent
carboxylases in a variety of microorganisms. The
strict control of biotin biosynthesis in
Escherichia coli is mediated by the bifunctional
BirA protein which acts both as a biotin-protein
ligase and a transcriptional repressor of the
biotin operon. Little is known about regulation of
biotin biosynthesis in other bacteria. Using
comparative genomics and phylogenetic analysis, we
described the biotin biosynthetic pathway and the
BirA regulon in the most available bacterial
genomes. The existence of N-terminal DNA-binding
(D-b) domain in BirA correlates strictly with the
presence of putative BirA-binding sites upstream of
biotin operons. The predicted BirA-binding sites
are well-conserved along various eubacterial and
archaeal genomes. The possible implication of the
hypothetical genes bioY and yhfS-yhfT, new members
of the BirA regulon, in biotin metabolism is
discussed. Based on the analysis of co-occurrence
of the biotin biosynthetic genes and bioY in
complete genomes, we predicted involvement of the
transmembrane BioY protein in biotin transport. The
non-orthologous displacements of the bioC-coupled
genes, namely bioH from E. coli, observed in
several genomes possibly represent the existence of
different pathways for the pimeloyl-CoA
biosynthesis. Another interesting result of
analysis of operon structures and the BirA sites is
that some biotin-dependent carboxylases from
Rhodobacter capsulatus, actinomycetes and archaea
are possibly co-regulated with BirA. The biotin
regulon is the first example of conservation of
transcriptional regulatory sites between bacteria
and archaea. |
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