Sequence-specific H NMR assignments and secondary structure in the sea anemone polypeptide Stichodactyla helianthus neurotoxin I

Sequence-specific assignments are reported for the 500-MHz H nuclear magnetic resonance (NMR) spectrum of the 48-residue polypeptide neurotoxin I from the sea anemone Stichodactyla helianthus (Sh I). Spin systems were first identified by using two-dimensional relayed or multiple quantum filtered cor...

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Bibliographic Details
Published in:Biochemistry (Easton) 1989-02, Vol.28:4
Main Authors: Fogh, R.H., Mabbutt, B.C., Kem, W.R., Norton, R.S.
Format: Article
Language:English
Subjects:
550601 - Medicine- Unsealed Radionuclides in Diagnostics
ANIMALS
ANTIGENS
AQUATIC ORGANISMS
BARYONS
CHEMICAL SHIFT
ELEMENTARY PARTICLES
FERMIONS
HADRONS
INVERTEBRATES
MAGNETIC RESONANCE
MATERIALS
MOLECULAR STRUCTURE
MOLLUSCS
NUCLEAR MAGNETIC RESONANCE
NUCLEONS
ORGANIC COMPOUNDS
OVERHAUSER EFFECT
PEPTIDES
POLYPEPTIDES
PROTEINS
PROTONS
RADIOLOGY AND NUCLEAR MEDICINE
RESONANCE
TOXIC MATERIALS
TOXINS
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Summary:Sequence-specific assignments are reported for the 500-MHz H nuclear magnetic resonance (NMR) spectrum of the 48-residue polypeptide neurotoxin I from the sea anemone Stichodactyla helianthus (Sh I). Spin systems were first identified by using two-dimensional relayed or multiple quantum filtered correlation spectroscopy, double quantum spectroscopy, and spin lock experiments. Specific resonance assignments were then obtained from nuclear Overhauser enhancement (NOE) connectivities between protons from residues adjacent in the amino acid sequence. Of a total of 265 potentially observable resonances, 248 (i.e., 94%) were assigned, arising from 39 completely and 9 partially assigned amino acid spin systems. The secondary structure of Sh I was defined on the basis of the pattern of sequential NOE connectivities. NOEs between protons on separate strands of the polypeptide backbone, and backbone amide exchange rates. Sh I contains a four-stranded antiparallel {beta}-sheet encompassing residues 1-5, 16-24, 30-33, and 40-46, with a {beta}-bulge at residues 17 and 18 and a reverse turn, probably a type II {beta}-turn, involving residues 27-30. No evidence of {alpha}-helical structure was found.
ISSN:0006-2960
1520-4995
DOI:10.1021/bi00430a060