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Structure of synthetic peptide analogues of an eggshell protein of Schistosoma mansoni
Author(s) -
Middaugh C. Russell,
Ryan James A.,
Burke Carl J.,
Mach Henryk,
Naylor Adel M.,
Bogusky Michael J.,
Pitzenberger Steven M.,
Ji Hanlee,
Cordingley John S.,
Thomson John A.
Publication year - 1993
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1002/pro.5560020604
Subject(s) - peptide , chemistry , schistosoma mansoni , circular dichroism , polyproline helix , peptide sequence , stereochemistry , helix (gastropod) , crystallography , protein structure , amino acid , biochemistry , biology , schistosomiasis , zoology , ecology , snail , gene , helminths
The peptide (Gly‐l‐Tyr‐l‐Asp‐l‐Lys‐l‐Tyr) 6 , referred to as F4–6, was synthesized as a model for a schistosome eggshell protein in which the Gly‐Tyr‐Asp‐Lys‐Tyr consensus sequence is repeated over 40 times. Analysis by CD, Fourier transform infrared spectroscopy, potentiometric and spectrophotometric titrations, NMR, and molecular modeling suggests that F4–6 forms some type of left‐handed structure. A likely possibility appears to be a left‐handed α ‐helix stabilized by Lys i ‐Asp i +4 salt bridges and possibly Asp i ‐Tyr i +4 hydrogen bonding and Tyr‐Tyr interactions. Spectroscopic studies of a number of F4–6 analogues support this conclusion. For example, substitution of d‐Ala for Gly produces a peptide with enhanced left‐handed helical spectral characteristics, whereas an l‐Ala substitution results in a peptide with minimal structure. These studies suggest that the F4 protein from Schistosoma mansoni may be the first example of a naturally occurring protein devoid of proline and carbohydrate that forms a left‐handed helix composed of l‐amino acids, although alternative forms of other left‐handed structures have yet to be rigorously excluded.