Disease relevance of bioB

• The OK2 strain would only cross-feed with the Escherichia coli bioB mutant and also grew well in medium containing dethiobiotin [1].
• Biotin synthase of Bacillus subtilis shows less reactivity than that of Escherichia coli in in vitro reaction systems [2].

High impact information on bioB

• Reductive cleavage of S-adenosylmethionine by biotin synthase from Escherichia coli [3].
• Biotin synthase (BioB) catalyzes the insertion of a sulfur atom between the C6 and C9 carbons of dethiobiotin [3].
• We conclude that three of the conserved cysteine residues (Cys-53, Cys-57, and Cys-60), all of which lie in the highly conserved "cysteine box" motif, are crucial for [Fe-S] cluster binding, whereas Cys-188 plays a hitherto unknown structural role in biotin synthase [4].
• The gene encoding Escherichia coli biotin synthase (bioB) has been expressed as a histidine fusion protein, and the protein was purified in a single step using immobilized metal affinity chromatography [4].
• The operon is negatively regulated and divergently transcribed from a control region between the bioA and bioB genes [5].

Chemical compound and disease context of bioB

• To investigate the role of the cysteine residues, Cys-->Ala mutants of the eight cysteine residues of Escherichia coli biotin synthase were prepared and assayed for activity [6].
• In Escherichia coli, biotin synthase (bioB gene product) catalyzes the key step in the biotin biosynthetic pathway, converting dethiobiotin (DTB) to biotin [7].
• Escherichia coli biotin synthase produces selenobiotin. Further evidence of the involvement of the [2Fe-2S]2+ cluster in the sulfur insertion step [8].

Biological context of bioB

• A recombinant plasmid pSB01, containing an 8.2-kb DNA fragment from B. sphaericus, was isolated by phenotypic complementation of an Escherichia coli bioB strain [9].
• Nucleotide sequence analysis of this fragment and N-terminal sequence determination of the recombinant protein product revealed that the bioB gene of B. sphaericus consists of a 996-bp open reading frame which is closely associated with at least one other gene [9].
• Two other point mutations, which were both GC-->AT changes just before and after the initiation codon of the bioB gene, were considered to activate the translation efficiency [10].
• These results suggest that this phenotype of growth inhibition by overexpression of the bioB gene in E. coli is independent of the biotin-forming activity itself, but is caused by some function involving a specific conformation of the bioB gene product [11].
• This growth inhibition was still observed when the wild-type bioB gene was replaced by several mutant-type bioB genes derived from biotin auxotrophs that have base-pair substitutions creating amino acid substitutions in the bioB gene product [11].

Anatomical context of bioB

• Biochemical characterization of the Arabidopsis biotin synthase reaction. The importance of mitochondria in biotin synthesis [12].

Associations of bioB with chemical compounds

• The [4Fe-4S](2+) cluster in reconstituted biotin synthase binds S-adenosyl-L-methionine [13].
• Although the name of the protein implies that it functions as an enzyme, it has been consistently reported that biotin synthase produces <1 molecule of biotin per molecule of protein in vitro [14].
• However, the modification of Ala 143 and Gly 99 of the bioB gene product resulted in recovery from growth inhibition [11].
• Biotin synthase catalyzes formation of a thiophane ring through a radical mechanism that is difficult to reconstitute in vitro [15].
• Lipoate synthase, which catalyzes the formation of two C-S bonds from octanoic acid, has a very high sequence similarity with biotin synthase [16].

Enzymatic interactions of bioB

• Biotin synthase catalyses the final step in the biotin biosynthetic pathway and is encoded by the bioB gene in Escherichia coli [17].

Other interactions of bioB

• In Escherichia coli, biotin synthase is coded for by bioB gene [18].

Analytical, diagnostic and therapeutic context of bioB

• Structure-function studies of Escherichia coli biotin synthase via a chemical modification and site-directed mutagenesis approach [7].
• Evidence from Mössbauer spectroscopy for distinct [2Fe-2S](2+) and [4Fe-4S](2+) cluster binding sites in biotin synthase from Escherichia coli [19].

References