DNA-binding and enzymatic domains of the bifunctional biotin operon repressor (BirA) of Escherichia coli.
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Buoncristiani MR, Howard PK, Otsuka AJ
DNA-binding and enzymatic domains of the bifunctional biotin operon repressor (BirA) of Escherichia coli.
Gene. 1986;44(2-3):255-61.
- PubMed ID
- 3536662 [ View in PubMed]
- Abstract
The negative regulation of the biotin biosynthetic (bio) operon in Escherichia coli is mediated by the bifunctional birA gene product, which serves as the bio repressor and biotin-activating enzyme. Nucleotide sequence analysis of 18 mutations in the birA gene was employed to study the DNA-binding and enzymatic functions of the BirA protein. The results indicate that a predicted helix-turn-helix structure, from amino acid (aa) positions 18 to 39 within the 321-aa BirA protein, may be responsible for sequence-specific DNA binding, whereas the temperature-sensitive mutations affecting biotin activation are found in two regions from aa positions 83-119 and 189-235.