1JBA

UNMYRISTOYLATED GCAP-2 WITH THREE CALCIUM IONS BOUND

Summary for 1JBA

• Entry DOI: 10.2210/pdb1jba/pdb
• NMR Information: BMRB: 4492
• Descriptor: PROTEIN (GUANYLATE CYCLASE ACTIVATING PROTEIN 2), CALCIUM ION (2 entities in total)
• Functional Keywords: ef-hand, calcium-binding protein, guanylyl cyclase regulation, lyase
• Biological source: Bos taurus (cattle)
• Cellular location: Cell membrane: P51177
• Total number of polymer chains: 1
• Total formula weight: 23875.08

Authors

Ames, J.B.,Dizhoor, A.M.,Ikura, M.,Palczewski, K.,Stryer, L. (deposition date: 1999-04-03, release date: 1999-12-10, Last modification date: 2023-12-27)

Primary citation

Ames, J.B.,Dizhoor, A.M.,Ikura, M.,Palczewski, K.,Stryer, L.
Three-dimensional structure of guanylyl cyclase activating protein-2, a calcium-sensitive modulator of photoreceptor guanylyl cyclases.
J.Biol.Chem., 274:19329-19337, 1999

PubMed Abstract: 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.

PubMed: 10383444
DOI: 10.1074/jbc.274.27.19329

Experimental method

SOLUTION NMR