Premium
The effects of L ‐ to D ‐isomerization and C‐terminus deamidation on the secondary structure of antimicrobial peptide Anoplin in aqueous and membrane mimicking environment
Author(s) -
Pripotnev Stahs,
Won Amy,
Ianoul Anatoli
Publication year - 2010
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.2608
Subject(s) - chemistry , deamidation , random coil , peptide , aqueous solution , membrane , vesicle , circular dichroism , antimicrobial peptides , isomerization , stereochemistry , biophysics , organic chemistry , biochemistry , catalysis , enzyme , biology
UV resonance Raman spectra of the antimicrobial peptide (AMP) Anoplin ( L ‐Anoplin‐NH 2 ) and two of its derivatives (enantiomer D ‐Anoplin‐NH 2 and C‐terminus deamidated L ‐Anoplin‐OH) were measured in aqueous buffer solution and in membrane‐mimetic environments including 2,2,2‐trifluoro ethanol (TFE), zwitterionic lipid dipalmitoylglycerophosphocholine (DPPC) and anionic lipid dipalmitoylglycerophosphoglycerol (DPPG) vesicle solutions. All three peptides were found to adopt random‐coil/β turn‐like conformation in aqueous solution over the temperature range of 1–60 °C. The conformation was found to become more α‐helical in membrane‐mimetic solutions such as TFE and DPPG but not in DPPC for all Anoplin derivatives. The data demonstrate that Anoplin preferentially binds to the anionic over the zwitterionic model cell membranes. Results also showed that deamidation does not change the conformation of L ‐Ano‐NH 2 very significantly, but does alter membrane rupturing and antimicrobial activities thus confirming that it is the physicochemical properties rather than the peptide conformation that define the mechanism of AMP action. Copyright © 2010 John Wiley & Sons, Ltd.