1RL3

Crystal structure of cAMP-free R1a subunit of PKA

Summary for 1RL3

• Entry DOI: 10.2210/pdb1rl3/pdb
• Related: 1NE4 1NE6 1RGS
• Descriptor: cAMP-dependent protein kinase type I-alpha regulatory chain, CYCLIC GUANOSINE MONOPHOSPHATE, GLYCEROL, ... (4 entities in total)
• Functional Keywords: type 1a regulatory subunit, camp-dependent protein kinase, camp-free, kinase
• Biological source: Bos taurus (cattle)
• Total number of polymer chains: 2
• Total formula weight: 65954.40

Authors

Wu, J.,Brown, S.,Xuong, N.-H.,Taylor, S.S. (deposition date: 2003-11-24, release date: 2004-07-06, Last modification date: 2023-08-23)

Primary citation

Wu, J.,Brown, S.,Xuong, N.H.,Taylor, S.S.
RIalpha subunit of PKA: a cAMP-free structure reveals a hydrophobic capping mechanism for docking cAMP into site B.
Structure, 12:1057-1065, 2004

PubMed Abstract: In eukaryotes the primary target for cAMP, a ubiquitous second messenger, is cAMP-dependent protein kinase (PKA). Understanding how binding and release of cAMP changes the cAMP binding domains and then triggers long-range allosteric responses is an important challenge. This conformational switching requires structure solutions of cAMP binding domains in cAMP-bound and cAMP-free states. We describe for the first time a crystal structure of the cAMP binding domains of PKA type Ialpha regulatory subunit where site A is occupied by cGMP and site B is unoccupied. The structure reveals that the carboxyl terminus of domain B serves as a hydrophobic cap, locking the cyclic nucleotide via its adenine ring into the beta-barrel. In the absence of cAMP, the "cap" is released via an extension of the C-terminal helix. This simple hinge mechanism for binding and release of cAMP also provides a mechanism for allosteric communication between sites A and B.

PubMed: 15274925
DOI: 10.1016/j.str.2004.03.022

Experimental method

X-RAY DIFFRACTION (2.7 Å)