Structural determinants of the PDE6 GAF A domain for binding the inhibitory gamma-subunit and noncatalytic cGMP.
Photoreceptor cGMP phosphodiesterases (PDE6 family) are modular enzymes with each catalytic subunit containing two N-terminal regulatory GAF domains, GAF A and GAF B. The GAF A domains contribute to dimerization of the PDE6 catalytic subunits and to binding of the inhibitory Pgamma subunits, and represent candidate sites for noncatalytic binding of cGMP. We performed a mutational analysis of selected residues from the GAF A domain of cone PDEalpha' to identify the cGMP-binding pocket and delineate the Pgamma-binding surface. Results of this analysis establish the noncatalytic cGMP-binding site within the PDE6 GAF A domain and suggest that occupation of the pocket by cGMP is required for high-affinity binding of Pgamma to the proximate contact surface.
Muradov
Hakim
H
Department of Physiology and Biophysics, University of Iowa College of Medicine, 5-532 Bowen Science Bldg., 51 Newton Road, Iowa City, IA 52242, USA.
Boyd
Kimberly K
KK
Artemyev
Nikolai O
NO
D015106:3',5'-Cyclic-GMP Phosphodiesterases / Q000235:genetics* / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D020134:Catalytic Domain; D002417:Cattle; D006152:Cyclic GMP / Q000378:metabolism*; D054707:Cyclic Nucleotide Phosphodiesterases, Type 6; D005136:Eye Proteins; D006801:Humans; D051379:Mice; D008958:Models, Molecular; D016296:Mutagenesis; D011485:Protein Binding; D016415:Sequence Alignment; D013329:Structure-Activity Relationship
D005136:Eye Proteins; D015106:3',5'-Cyclic-GMP Phosphodiesterases; D054707:Cyclic Nucleotide Phosphodiesterases, Type 6; C410522:PDE6A protein, human; C498747:Pde6a protein, mouse; D006152:Cyclic GMP