2dpr
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(New page: 200px<br /><applet load="2dpr" size="350" color="white" frame="true" align="right" spinBox="true" caption="2dpr, resolution 1.7Å" /> '''The crystal structure...)
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Revision as of 13:33, 23 January 2008
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The crystal structures of the calcium-bound con-G and con-T(K7Gla) dimeric peptides demonstrate a novel metal-dependent helix-forming motif
Overview
Short peptides that have the ability to form stable alpha-helices in, solution are rare, and a number of strategies have been used to produce, them, including the use of metal chelation to stabilize folding of the, backbone. However, no example exists of a structurally well-defined helix, stabilized exclusively through metal ion chelation. Conantokins (con)-G, and -T are short peptides that are potent antagonists of, N-methyl-D-aspartate receptor channels. While con-G exhibits no helicity, alone, it undergoes a structural transition to a helical conformation in, the presence of a variety of multivalent cations, especially Mg2+ and, Ca2+. This complexation also results in antiparallel dimerization of two, peptide helices in the presence of Ca2+, but not Mg2+. A con-T variant, con-T[K7gamma], displays very similar behavior. We have solved the crystal, structures of both Ca2+/con-G and Ca2+/con-T [K7gamma] at atomic, resolution. These structures clearly show the nature of the, metal-dependent dimerization and helix formation and surprisingly also, show that the con-G dimer interface is completely different from the, con-T[K7gamma] interface, even though the metal chelation is similar in, the two peptides. This represents a new paradigm in helix stabilization, completely independent of the hydrophobic effect, which we define as the, "metallo-zipper."
About this Structure
2DPR is a Protein complex structure of sequences from [1] with as ligand. Full crystallographic information is available from OCA.
Reference
The crystal structures of the calcium-bound con-G and con-T[K7gamma] dimeric peptides demonstrate a metal-dependent helix-forming motif., Cnudde SE, Prorok M, Dai Q, Castellino FJ, Geiger JH, J Am Chem Soc. 2007 Feb 14;129(6):1586-93. Epub 2007 Jan 23. PMID:17243678
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