Sequence-specific 1H NMR assignments and secondary structure in the sea anemone polypeptide Stichodactyla helianthus neurotoxin I

Rasmus H. Fogh, Bridget C. Mabbutt, William R. Kem, Raymond S. Norton*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)

Abstract

Sequence-specific assignments are reported for the 500-MHz 1H 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 β-sheet encompassing residues 1-5, 16-24, 30-33, and 40-46, with a β-bulge at residues 17 and 18 and a reverse turn, probably a type II α-turn, involving residues 27-30. No evidence of α-helical structure was found.

Original languageEnglish
Pages (from-to)1826-1834
Number of pages9
JournalBiochemistry
Volume28
Issue number4
Publication statusPublished - 1989
Externally publishedYes

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