PDBsum entry 1ad7

Gamma-carboxyglutamic acid

PDB id: 1ad7

Contents

Protein chain

18 a.a.

PDB id:

1ad7

Name:

Gamma-carboxyglutamic acid

Title:

Nmr structure of metal-free conantokin g, 1 structure

Structure:

Conantoxin g. Chain: a. Engineered: yes

Source:

Synthetic: yes. Conus geographus. Organism_taxid: 6491. Other_details: c-terminal amide, synthetic peptide

NMR struc:

1 models

Authors:

A.C.Rigby,J.D.Baleja,B.C.Furie,B.Furie

Key ref:

A.C.Rigby et al. (1997). 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. PubMed id: 9188685 DOI: 10.1021/bi970321w

Date:

21-Feb-97 Release date: 20-Aug-97

Protein chain

P07231  (CKG_CONGE) -  Conantokin-G from Conus geographus

Seq: 100 a.a.

Struc: 18 a.a.*

* PDB and UniProt seqs differ at 6 residue positions (black crosses)

Enzyme reactions

• Enzyme class: E.C.?

DOI no: 10.1021/bi970321w

Biochemistry 36:6906-6914 (1997)

PubMed id: 9188685

Three-dimensional structure of a gamma-carboxyglutamic acid-containing conotoxin, conantokin G, from the marine snail Conus geographus: the metal-free conformer.

A.C.Rigby, J.D.Baleja, B.C.Furie, B.Furie.

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.