4JV4

Crystal Structure of RIalpha(91-379) bound to HE33, a N6 di-propyl substituted cAMP analog

Summary for 4JV4

• Entry DOI: 10.2210/pdb4jv4/pdb
• Related: 1NE4 1NE6 1RGS
• Descriptor: cAMP-dependent protein kinase type I-alpha regulatory subunit, (2R,4aR,6R,7R,7aS)-6-[6-(dipropylamino)-9H-purin-9-yl]tetrahydro-4H-furo[3,2-d][1,3,2]dioxaphosphinine-2,7-diol 2-oxide (2 entities in total)
• Functional Keywords: camp-dependent protein kinase, cyclic nucleotide analogs, isoform selectivity, fluorescence anisotropy, transferase-transferase inhibitor complex, transferase/transferase inhibitor
• Biological source: Bos taurus (bovine,cow,domestic cattle,domestic cow)
• Cellular location: Cell membrane (By similarity): P00514
• Total number of polymer chains: 1
• Total formula weight: 33320.58

Authors

Brown, S.H.J.,Cheng, C.Y.,Saldanha, A.S.,Wu, J.,Cottam, H.,Sankaran, B.,Taylor, S.S. (deposition date: 2013-03-25, release date: 2013-09-18, Last modification date: 2023-09-20)

Primary citation

Brown, S.H.,Cheng, C.Y.,Saldanha, S.A.,Wu, J.,Cottam, H.B.,Sankaran, B.,Taylor, S.S.
Implementing Fluorescence Anisotropy Screening and Crystallographic Analysis to Define PKA Isoform-Selective Activation by cAMP Analogs.
Acs Chem.Biol., 8:2164-2172, 2013

PubMed Abstract: Cyclic AMP (cAMP) is a ubiquitous second messenger that regulates many proteins, most notably cAMP-dependent protein kinase (PKA). PKA holoenzymes (comprised of two catalytic (C) and two regulatory (R) subunits) regulate a wide variety of cellular processes, and its functional diversity is amplified by the presence of four R-subunit isoforms, RIα, RIβ, RIIα, and RIIβ. Although these isoforms all respond to cAMP, they are functionally nonredundant and exhibit different biochemical properties. In order to understand the functional differences between these isoforms, we screened cAMP derivatives for their ability to selectively activate RI and RII PKA holoenzymes using a fluorescence anisotropy assay. Our results indicate that RIα holoenzymes are selectively activated by C8-substituted analogs and RIIβ holoenzymes by N6-substituted analogs, where HE33 is the most prominent RII activator. We also solved the crystal structures of both RIα and RIIβ bound to HE33. The RIIβ structure shows the bulky aliphatic substituent of HE33 is fully encompassed by a pocket comprising of hydrophobic residues. RIα lacks this hydrophobic lining in Domain A, and the side chains are displaced to accommodate the HE33 dipropyl groups. Comparison between cAMP-bound structures reveals that RIIβ, but not RIα, contains a cavity near the N6 site. This study suggests that the selective activation of RII over RI isoforms by N6 analogs is driven by the spatial and chemical constraints of Domain A and paves the way for the development of potent noncyclic nucleotide activators to specifically target PKA iso-holoenyzmes.

PubMed: 23978166
DOI: 10.1021/cb400247t

Experimental method

X-RAY DIFFRACTION (2.952 Å)