2DPR

The crystal structures of the calcium-bound con-G and con-T(K7Glu) dimeric peptides demonstrate a novel metal-dependent helix-forming motif

Summary for 2DPR

• Entry DOI: 10.2210/pdb2dpr/pdb
• Related: 2DPQ
• Descriptor: Conantokin-T, CALCIUM ION (3 entities in total)
• Functional Keywords: conantoxin, con-t, nmdar antagonist, gla-containing, metal binding protein
• Biological source: Conus tulipa (fish-hunting cone snail)
• Cellular location: Secreted : P17684
• Total number of polymer chains: 2
• Total formula weight: 5625.86

Authors

Cnudde, S.E.,Prorok, M.,Dai, Q.,Castellino, F.J.,Geiger, J.H. (deposition date: 2006-05-13, release date: 2007-04-24, Last modification date: 2024-04-03)

Primary citation

Cnudde, S.E.,Prorok, M.,Dai, Q.,Castellino, F.J.,Geiger, J.H.
The crystal structures of the calcium-bound con-G and con-T[K7gamma] dimeric peptides demonstrate a metal-dependent helix-forming motif
J.Am.Chem.Soc., 129:1586-1593, 2007

PubMed Abstract: 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."

PubMed: 17243678
DOI: 10.1021/ja065722q

Experimental method

X-RAY DIFFRACTION (1.7 Å)