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1jba
From Proteopedia
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[[Image:1jba.jpg|left|200px]] | [[Image:1jba.jpg|left|200px]] | ||
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'''UNMYRISTOYLATED GCAP-2 WITH THREE CALCIUM IONS BOUND''' | '''UNMYRISTOYLATED GCAP-2 WITH THREE CALCIUM IONS BOUND''' | ||
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[[Category: Palczewski, K.]] | [[Category: Palczewski, K.]] | ||
[[Category: Stryer, L.]] | [[Category: Stryer, L.]] | ||
| - | [[Category: | + | [[Category: Calcium-binding protein]] |
| - | [[Category: | + | [[Category: Ef-hand]] |
| - | [[Category: | + | [[Category: Guanylyl cyclase regulation]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 21:00:36 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 18:00, 2 May 2008
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 Page seeded by OCA on Fri May 2 21:00:36 2008
