Download MendeleyCrystal structure of (73-244)RIa:C holoenzyme of cAMP-dependent Protein kinase
Boettcher, A.J., Wu, J., Kim, C., Yang, J., Bruystens, J., Cheung, N., Pennypacker, J.K., Blumenthal, D.A., Kornev, A.P., Taylor, S.S.(2011) Structure 19: 265-276
- PubMed: 21300294
- DOI: https://doi.org/10.1016/j.str.2010.12.005
- Primary Citation of Related Structures:
3PVB - PubMed Abstract:
PKA holoenzymes containing two catalytic (C) subunits and a regulatory (R) subunit dimer are activated cooperatively by cAMP. While cooperativity involves the two tandem cAMP binding domains in each R-subunit, additional cooperativity is associated with the tetramer. Of critical importance is the flexible linker in R that contains an inhibitor site (IS). While the IS becomes ordered in the R:C heterodimer, the overall conformation of the tetramer is mediated largely by the N-Linker that connects the D/D domain to the IS. To understand how the N-Linker contributes to assembly of tetrameric holoenzymes, we engineered a monomeric RIα that contains most of the N-Linker, RIα(73-244), and crystallized a holoenzyme complex. Part of the N-linker is now ordered by interactions with a symmetry-related dimer. This complex of two symmetry-related dimers forms a tetramer that reveals novel mechanisms for allosteric regulation and has many features associated with full-length holoenzyme. A model of the tetrameric holoenzyme, based on this structure, is consistent with previous small angle X-ray and neutron scattering data, and is validated with new SAXS data and with an RIα mutation localized to a novel interface unique to the tetramer.
Organizational Affiliation:
Department of Chemistry and Biochemistry, University of California at San Diego, La Jolla, CA 92093, USA.
