1COD

SOLUTION CONFORMATION OF COBROTOXIN: A NUCLEAR MAGNETIC RESONANCE AND HYBRID DISTANCE GEOMETRY-DYNAMICAL SIMULATED ANNEALING STUDY

Summary for 1COD

• Entry DOI: 10.2210/pdb1cod/pdb
• Descriptor: COBROTOXIN (1 entity in total)
• Functional Keywords: short neurotoxin
• Biological source: Naja atra (Chinese cobra)
• Total number of polymer chains: 1
• Total formula weight: 6967.68

Authors

Yu, C.,Bhaskaran, R.,Yang, C.C. (deposition date: 1994-05-11, release date: 1995-01-26, Last modification date: 2024-11-06)

Primary citation

Yu, C.,Bhaskaran, R.,Chuang, L.C.,Yang, C.C.
Solution conformation of cobrotoxin: a nuclear magnetic resonance and hybrid distance geometry-dynamical simulated annealing study.
Biochemistry, 32:2131-2136, 1993

PubMed Abstract: The solution conformation of cobrotoxin has been determined by using proton nuclear magnetic resonance spectroscopy. With the combination of various two-dimensional NMR techniques, the 1H-NMR spectrum of cobrotoxin was completely assigned (Yu et al., 1990). A set of 435 approximate interproton distance restraints was derived from nuclear Overhauser enhancement (NOE) measurements. These NOE constraints, in addition to the 29 dihedral angle constraints (from coupling constant measurements) and 26 hydrogen bonding restraints (from the pattern of short-range NOEs), form the basis of 3-D structure determination by the hybrid distance geometry-dynamical simulated annealing method. The 23 structures that were obtained satisfy the experimental restraints, display small deviation from idealized covalent geometry, and possess good nonbonded contacts. Analysis of converged structures indicated that there are two antiparallel beta sheets (double and triple stranded), duly confirming our earlier observations. These are well defined in terms of both atomic root mean square (RMS) differences and backbone torsional angles. The average backbone RMS deviation between the calculated structures and the mean structure, for the beta-sheet regions, is 0.92 A. The mean solution structure was compared with the X-ray crystal structure of erabutoxin b, the homologous protein. This yielded information that both structures resemble each other except at the exposed loop/surface regions, where the solution structure seems to possess more flexibility.

PubMed: 8443154
DOI: 10.1021/bi00060a002

Experimental method

SOLUTION NMR