title: Structural analyses of a constitutively active mutant of exchange protein directly activated by cAMP.
abstract: Exchange proteins directly activated by cAMP (EPACs) are important allosteric regulators of cAMP-mediated signal transduction pathways. To understand the molecular mechanism of EPAC activation, we have combined site-directed mutagenesis, X-ray crystallography, and peptide amide hydrogen/deuterium exchange mass spectrometry (DXMS) to probe the structural and conformational dynamics of EPAC2-F435G, a constitutively active EPAC2 mutant. Our study demonstrates that conformational dynamics plays a critical role in cAMP-induced EPAC activation. A glycine mutation at 435 position shifts the equilibrium of conformational dynamics towards the extended active conformation.
authors.affiliation: Sealy Center for Structural Biology and Molecular Biophysics, The University of Texas Medical Branch, Galveston, Texas, United States of America.
authors.forename: Mark A
authors.initials: MA
authors.lastname: White
authors.forename: Sheng
authors.initials: S
authors.lastname: Li
authors.forename: Tamara
authors.initials: T
authors.lastname: Tsalkova
authors.forename: Fang C
authors.initials: FC
authors.lastname: Mei
authors.forename: Tong
authors.initials: T
authors.lastname: Liu
authors.forename: Virgil L
authors.initials: VL
authors.lastname: Woods
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Cheng
mesh_terms: D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D000242:Cyclic AMP / Q000737:chemistry / Q000378:metabolism; D003903:Deuterium / Q000737:chemistry; D020662:Guanine Nucleotide Exchange Factors / Q000737:chemistry* / Q000235:genetics; D006801:Humans; D006859:Hydrogen / Q000737:chemistry; D008958:Models, Molecular; D009154:Mutation; D011485:Protein Binding; D011487:Protein Conformation; D054730:Protein Interaction Domains and Motifs
chemical_list: D020662:Guanine Nucleotide Exchange Factors; C116122:RAPGEF3 protein, human; D006859:Hydrogen; D003903:Deuterium; D000242:Cyclic AMP