1jba

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spinqualitylabelsall models PDB ID 1jba Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image
Ligands:
Activity:	Guanylate cyclase, with EC number 4.6.1.2
Resources:	FirstGlance, OCA, PDBsum, RCSB
Coordinates:	save as pdb, mmCIF, xml

UNMYRISTOYLATED GCAP-2 WITH THREE CALCIUM IONS BOUND

Overview

Guanylyl cyclase activating protein-2 (GCAP-2) is a Ca2+-sensitive regulator of phototransduction in retinal photoreceptor cells. GCAP-2 activates retinal guanylyl cyclases at low Ca2+ concentration (<100 nM) and inhibits them at high Ca2+ (>500 nM). The light-induced lowering of the Ca2+ level from approximately 500 nM in the dark to approximately 50 nM following illumination is known to play a key role in visual recovery and adaptation. We report here the three-dimensional structure of unmyristoylated GCAP-2 with three bound Ca2+ ions as determined by nuclear magnetic resonance spectroscopy of recombinant, isotopically labeled protein. GCAP-2 contains four EF-hand motifs arranged in a compact tandem array like that seen previously in recoverin. The root mean square deviation of the main chain atoms in the EF-hand regions is 2.2 A in comparing the Ca2+-bound structures of GCAP-2 and recoverin. EF-1, as in recoverin, does not bind calcium because it contains a disabling Cys-Pro sequence. GCAP-2 differs from recoverin in that the calcium ion binds to EF-4 in addition to EF-2 and EF-3. A prominent exposed patch of hydrophobic residues formed by EF-1 and EF-2 (Leu24, Trp27, Phe31, Phe45, Phe48, Phe49, Tyr81, Val82, Leu85, and Leu89) may serve as a target-binding site for the transmission of calcium signals to guanylyl cyclase.

About this Structure

1JBA is a Single protein structure of sequence from Bos taurus. Full crystallographic information is available from OCA.

Reference

Three-dimensional structure of guanylyl cyclase activating protein-2, a calcium-sensitive modulator of photoreceptor guanylyl cyclases., Ames JB, Dizhoor AM, Ikura M, Palczewski K, Stryer L, J Biol Chem. 1999 Jul 2;274(27):19329-37. PMID:10383444

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