Open AccessSolution conformation of an antibacterial peptide, sarcotoxin IA, as determined by 1 H‐NMR
Author(s) -
IWAI Hideo,
NAKAJIMA Yuki,
NATORI Shunji,
ARATA Yoji,
SHIMADA Ichio
Publication year - 1993
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1993.tb18287.x
Subject(s) - amphiphile , helix (gastropod) , chemistry , crystallography , peptide , hydrogen bond , nuclear magnetic resonance spectroscopy , stereochemistry , circular dichroism , two dimensional nuclear magnetic resonance spectroscopy , proton nmr , molecule , biochemistry , organic chemistry , biology , copolymer , ecology , snail , polymer
The solution conformation of sarcotoxin IA, which is an antibacterial peptide isolated from Sarcophaga peregrina with a molecular mass of 4 kDa, was determined by NMR spectroscopy and hybrid distance geometry/dynamical simulated annealing calculations. On the basis of 227 experimental constraints, including 185 distance constraints obtained from NOE and 42 constraints associated with 21 hydrogen bonds, a total of 18 converged structures of sarcotoxin IA were obtained. The final 18 converged structures exhibit backbone‐atomic root‐mean‐square differences about the averaged coordinate positions of 0.070±0.027 nm for residues 3–23 and 0.040±0.017 nm for residues 28–38. It has been indicated that sarcotoxin IA consists of two amphiphilic α‐helical regions, i.e. helix I (Leu3–Gln23) and helix II (Ala28–Ala38), with a hinge region (Gly24–Ile27), which connects helix I and helix II. We conclude that these two amphiphilic helical segments of sarcotoxin IA are of importance for the expression of the antibacterial activity.