Sequential Individual Resonance Assignments in the 1H Nuclear‐Magnetic‐Resonance Spectrum of Cardiotoxin VII 2 from Naja mossambica mossambica

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Abstract
The assignment of the 1H NMR spectrum of cardiotoxin VII2 from N. m. mossambica was described and documented. The assignments were based on the amino acid sequence and on 2-dimensional NMR experiments at 500 MHz. Individual assignments were obtained at 45.degree. C for the backbone protons of 56 of the total 60 amino acid residues, the exceptions being the N-terminal dipeptide segment Leu-1.sbd.Lys-2.sbd., Pro-8 and Pro-15. Complete assignments of the nonlabile H atoms of the side chains were obtained for 37 residues, and for Asn-4 and Asn-19 the .delta. amide protons were also identified. For 19 long side chains the individual assignments included only the backbone and C-.beta. proton resonances; these were Gln-5, Pro-9, Pro-33, Pro-43, Leu-47, all 3 methionines, 2 arginines and 9 lysines. The chemical shifts for the assigned resonances at 45.degree. C were listed for an aqueous solution at pH 3.6. A preliminary interpretation of the sequential connectivity patterns indicated that .apprx. 30 of the total 60 amino acid residues in cardiotoxin VII2 were in extended, .beta.-type secondary structures, and there was no indication for the formation of .alpha.-helical structure.