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Left handed α‐helix formation by a bacterial peptide
Author(s) -
Mortishire-Smith Russel J.,
Drake Alex F.,
Nutkins Jennifer C.,
Williams Dudley H.
Publication year - 1991
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(91)80126-n
Subject(s) - mushroom , agaricus bisporus , circular dichroism , helix (gastropod) , alpha helix , peptide , amino acid , biology , biochemistry , peptide sequence , protein secondary structure , chemistry , stereochemistry , gene , botany , ecology , snail
The α‐helix is a common element of secondary structure in proteins and peptides. In eukaryotic organisms, which exclusively incorporate L‐amino acids into such molecules, stereochemical interactions make such α‐helices, invariably right‐handed. Pseudomonas tolaasii Paine is the causal organism of the economically significant brown blotch disease of the cultivated mushroom Agaricus bisporus (Lange) Imbach. P. tolaasii proceduces an extracellular lipodepsipeptide toxin, tolaasin, which causes the brown pitted lesions on the mushroom cap. Circular dichroism studies tolaasin in a membrane‐like environment indicate the presence of a left‐handed α‐helix, probably formed by a sequence of 7 D‐amino acids in the peptide. P. tolaasii represents the first reported example of an organism which has evolved the ability to biosynthesize a left‐handed α‐helix.