Nucleation of an allosteric response via ligand-induced loop folding.

ABSTRACT: The Escherichia coli biotin repressor BirA is an allosteric transcription regulatory protein to which binding of the small ligand corepressor biotinyl-5'-AMP promotes homodimerization and subsequent DNA binding. Structural data indicate that the apo or unliganded repressor is characterized by four partially disordered loops that are ordered in the ligand-bound dimer. While three of these loops participate directly in the dimerization, the fourth, consisting of residues 212-234 is distal to the interface. This loop, which is ordered around the adenine ring of the adenylate moiety in the BirA.adenylate structure, is referred to as the adenylate-binding loop (ABL). Although residues in the loop do not interact directly with the ligand, a hydrophobic cluster consisting of a tryptophan and two

SUBMITTER: Naganathan S 

PROVIDER: S-EPMC2792881 | biostudies-literature | 2007 Oct

REPOSITORIES: biostudies-literature