ISSN:
1573-3904
Keywords:
Hemolysis
;
Monolayers
;
PMIRRAS
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract De novo designed extremely simplified amphipathic basicLeuiLysj (i = 2j) peptides of 8, 9 and 15residues were synthesized to clarify the mechanism of action of naturalcytotoxic and hemolytic small proteins or peptides. They proved to havestrong hemolytic activity towards human erythrocytes which increases withpeptide length. These peptides are highly surface active and form stablepeptidic films at the air/water interface. The sensitive and efficient FTIRmodulated polarization technique (PMIRRAS) allows one to obtain in situstructural and orientational information about the peptides at theinterface. A transition of secondary structure is observed: the shorterpeptides (8 and 9 residues) adopt β-sheet structures while the longerone (15 residues) is folded into an α-helix. In both cases, the peptideslie with the axis parallel to the interface. Their insertion into adimyristoylphosphatidylcholine monolayer can be followed from the increasein the surface and/or pressure of the films. In the mixed films, thepeptides adopt the same structure and orientation as observed at theair/water interface. Therefore, among the same series of peptides, atransition from β-sheet to α-helix occurs when the length increases(roughly 〉10 aa), but despite this drastic change both types ofstructures result in strongly hemolytic peptides.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1008818732003
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