1AD7

NMR STRUCTURE OF METAL-FREE CONANTOKIN G, 1 STRUCTURE

Summary for 1AD7

• Entry DOI: 10.2210/pdb1ad7/pdb
• Descriptor: CONANTOXIN G (1 entity in total)
• Functional Keywords: gamma-carboxyglutamic acid, conantokin g, conotoxin
• Biological source: Conus geographus
• Cellular location: Secreted: P07231
• Total number of polymer chains: 1
• Total formula weight: 2265.20

Authors

Rigby, A.C.,Baleja, J.D.,Furie, B.C.,Furie, B. (deposition date: 1997-02-21, release date: 1997-08-20, Last modification date: 2024-06-05)

Primary citation

Rigby, A.C.,Baleja, J.D.,Furie, B.C.,Furie, B.
Three-dimensional structure of a gamma-carboxyglutamic acid-containing conotoxin, conantokin G, from the marine snail Conus geographus: the metal-free conformer.
Biochemistry, 36:6906-6914, 1997

PubMed Abstract: Conantokin G is a gamma-carboxyglutamic acid-containing conotoxin from the venom of the marine cone snail Conus geographus. The 17-residue peptide, which contains five gamma-carboxyglutamic acid (Gla) residues and an amidated C-terminal asparagine amide, was synthesized chemically in a form identical to the natural conantokin G. To gain insight into the role of gamma-carboxyglutamic acid in the structure of this peptide, we determined the three-dimensional structure of conantokin G by 1H NMR and compared its structure to other conotoxins and to the gamma-carboxyglutamic acid-containing regions of the vitamin K-dependent blood-clotting proteins. Complete resonance assignments were made by two-dimensional 1H NMR spectroscopy in the absence of metal ions. NOE cross-peaks d(alphaN), d(NN), and d(betaN) provided interproton distance information, and vicinal spin-spin coupling constants 3J(HN alpha) were used to calculate phi torsion angles. Distance geometry and simulated annealing methods were used to derive 20 convergent structures from a set of 227 interproton distance restraints and 13 torsion angle measurements. The backbone rmsd to the geometric average for 20 final structures is 0.8 +/- 0.1 A. Conantokin G consists of a structured region commencing at Gla 3 and extending through arginine 13. This structure includes a partial loop centered around Gla 3 and Gla 4, a distorted type I turn between glutamine 6 and glutamine 9, and two type I turns involving Gla 10, leucine 11, and isoleucine 12 and arginine 13. Together, these two turns define approximately 1.6 turns of a distorted 3(10) helix. The observed structure possesses structural elements similar to those seen in the disulfide-linked conotoxins.

PubMed: 9188685
DOI: 10.1021/bi970321w

Experimental method

SOLUTION NMR