2pq3
From Proteopedia
| Line 1: | Line 1: | ||
[[Image:2pq3.gif|left|200px]] | [[Image:2pq3.gif|left|200px]] | ||
| - | + | <!-- | |
| - | + | The line below this paragraph, containing "STRUCTURE_2pq3", creates the "Structure Box" on the page. | |
| - | + | You may change the PDB parameter (which sets the PDB file loaded into the applet) | |
| - | + | or the SCENE parameter (which sets the initial scene displayed when the page is loaded), | |
| - | + | or leave the SCENE parameter empty for the default display. | |
| - | + | --> | |
| - | + | {{STRUCTURE_2pq3| PDB=2pq3 | SCENE= }} | |
| - | | | + | |
| - | | | + | |
| - | }} | + | |
'''N-Terminal Calmodulin Zn-Trapped Intermediate''' | '''N-Terminal Calmodulin Zn-Trapped Intermediate''' | ||
| Line 28: | Line 25: | ||
[[Category: Tang, W J.]] | [[Category: Tang, W J.]] | ||
[[Category: Warren, J T.]] | [[Category: Warren, J T.]] | ||
| - | [[Category: | + | [[Category: Calmodulin]] |
| - | [[Category: | + | [[Category: Cam]] |
| - | [[Category: | + | [[Category: Ef-hand]] |
| - | [[Category: | + | [[Category: Helix-turn-helix]] |
| - | [[Category: | + | [[Category: Metal binding protein]] |
| - | [[Category: | + | [[Category: N-cam]] |
| - | [[Category: | + | [[Category: N-terminal calmodulin]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun May 4 13:36:34 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 10:36, 4 May 2008
N-Terminal Calmodulin Zn-Trapped Intermediate
Overview
Calmodulin (CaM) is a 16.8-kDa calcium-binding protein involved in calcium-signal transduction. It is the canonical member of the EF-hand family of proteins, which are characterized by a helix-loop-helix calcium-binding motif. CaM is composed of N- and C-terminal globular domains (N-CaM and C-CaM), and within each domain there are two EF-hand motifs. Upon binding calcium, CaM undergoes a significant, global conformational change involving reorientation of the four helix bundles in each of its two domains. This conformational change upon ion binding is a key component of the signal transduction and regulatory roles of CaM, yet the precise nature of this transition is still unclear. Here, we present a 1.3-A structure of zinc-bound N-terminal calmodulin (N-CaM) solved by single-wavelength anomalous diffraction phasing of a selenomethionyl N-CaM. Our zinc-bound N-CaM structure differs from previously reported CaM structures and resembles calcium-free apo-calmodulin (apo-CaM), despite the zinc binding to both EF-hand motifs. Structural comparison with calcium-free apo-CaM, calcium-loaded CaM, and a cross-linked calcium-loaded CaM suggests that our zinc-bound N-CaM reveals an intermediate step in the initiation of metal ion binding at the first EF-hand motif. Our data also suggest that metal ion coordination by two key residues in the first metal-binding site represents an initial step in the conformational transition induced by metal binding. This is followed by reordering of the N-terminal region of the helix exiting from this first binding loop. This conformational switch should be incorporated into models of either stepwise conformational transition or flexible, dynamic energetic state sampling-based transition.
About this Structure
2PQ3 is a Single protein structure of sequence from Rattus norvegicus. Full crystallographic information is available from OCA.
Reference
A 1.3-A structure of zinc-bound N-terminal domain of calmodulin elucidates potential early ion-binding step., Warren JT, Guo Q, Tang WJ, J Mol Biol. 2007 Nov 23;374(2):517-27. Epub 2007 Sep 21. PMID:17942116 Page seeded by OCA on Sun May 4 13:36:34 2008
