3HIF

The crystal structure of apo wild type CAP at 3.6 A resolution.

Summary for 3HIF

• Entry DOI: 10.2210/pdb3hif/pdb
• Related: 3FWE
• Descriptor: Catabolite gene activator (1 entity in total)
• Functional Keywords: helix-turn-helix, camp binding domain, activator, camp, camp-binding, dna-binding, nucleotide-binding, transcription, transcription regulation, transcription regulator
• Biological source: Escherichia coli
• Total number of polymer chains: 6
• Total formula weight: 142034.63

Authors

Steitz, T.A.,Sharma, H.,Wang, J.,Kong, J.,Yu, S. (deposition date: 2009-05-19, release date: 2009-09-08, Last modification date: 2024-04-03)

Primary citation

Sharma, H.,Yu, S.,Kong, J.,Wang, J.,Steitz, T.A.
Structure of apo-CAP reveals that large conformational changes are necessary for DNA binding.
Proc.Natl.Acad.Sci.USA, 106:16604-16609, 2009

PubMed Abstract: The binding of cAMP to the Escherichia coli catabolite gene activator protein (CAP) produces a conformational change that enables it to bind specific DNA sequences and regulate transcription, which it cannot do in the absence of the nucleotide. The crystal structures of the unliganded CAP containing a D138L mutation and the unliganded WT CAP were determined at 2.3 and 3.6 A resolution, respectively, and reveal that the two DNA binding domains have dimerized into one rigid body and their two DNA recognition helices become buried. The WT structure shows multiple orientations of this rigid body relative to the nucleotide binding domain supporting earlier biochemical data suggesting that the inactive form exists in an equilibrium among different conformations. Comparison of the structures of the liganded and unliganded CAP suggests that cAMP stabilizes the active DNA binding conformation of CAP through the interactions that the N(6) of the adenosine makes with the C-helices. These interactions are associated with the reorientation and elongation of the C-helices that precludes the formation of the inactive structure.

PubMed: 19805344
DOI: 10.1073/pnas.0908380106

Experimental method

X-RAY DIFFRACTION (3.59 Å)