Open AccessStructure of the apo form of the catabolite control protein A (CcpA) from Bacillus megaterium with a DNA‐binding domain
Author(s) -
Singh Rajesh Kumar,
Palm Gottfried J.,
Panjikar Santosh,
Hinrichs Winfried
Publication year - 2007
Publication title -
acta crystallographica section f
Language(s) - English
Resource type - Journals
ISSN - 1744-3091
DOI - 10.1107/s1744309107008949
Subject(s) - ccpa , catabolite repression , repressor , lac repressor , dna , ternary complex , dna binding domain , helix bundle , bacillus megaterium , corepressor , chemistry , biochemistry , protein structure , biology , gene , transcription factor , genetics , enzyme , bacteria , mutant
Crystal structure determination of catabolite control protein A (CcpA) at 2.6 Å resolution reveals for the first time the structure of a full‐length apo‐form LacI‐GalR family repressor protein. In the crystal structures of these transcription regulators, the three‐helix bundle of the DNA‐binding domain has only been observed in cognate DNA complexes; it has not been observed in other crystal structures owing to its mobility. In the crystal packing of apo‐CcpA, the protein–protein contacts between the N‐terminal three‐helix bundle and the core domain consisted of interactions between the homodimers that were similar to those between the corepressor protein HPr and the CcpA N‐subdomain in the ternary DNA complex. In contrast to the DNA complex, the apo‐CcpA structure reveals large subdomain movements in the core, resulting in a complete loss of contacts between the N‐subdomains of the homodimer.