Document Detail

Post-translational amino acid isomerization: a functionally important D-amino acid in an excitatory peptide.
MedLine Citation:
PMID:  15561705     Owner:  NLM     Status:  MEDLINE    
The post-translational modification of an L- to a D-amino acid has been documented in relatively few gene products, mostly in small peptides under 10 amino acids in length. In this report, we demonstrate that a 46-amino acid polypeptide toxin has one D-phenylalanine at position 44, and that the epimerization from an L-Phe to a D-Phe has a dramatic effect on the excitatory effects of the peptide. In one electrophysiological assay carried out, the D-Phe-containing peptide was extremely potent, whereas the unmodified polypeptide had no biological activity, demonstrating that the chirality of the post-translationally modified amino acid is functionally significant. The peptide toxin analyzed, r11a, belongs to the I-gene superfamily of conotoxins that has four disulfide cross-links. The D-Phe in r11a is at the third amino acid from the C terminus, the same relative position from the C-terminal end as the d-amino acid in omega-agatoxin TK from a spider, an unrelated peptide. Thus, although post-translational amino acid isomerization appears to have no strong specificity for the chemical nature of the amino acid side chain, the few peptides where this modification has been established suggest that there may be favored positions near the N or C terminus that are preferential sites for isomerization to a D-amino acid.
Olga Buczek; Doju Yoshikami; Grzegorz Bulaj; Elsie C Jimenez; Baldomero M Olivera
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.     Date:  2004-11-23
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  280     ISSN:  0021-9258     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  2005 Feb 
Date Detail:
Created Date:  2005-02-07     Completed Date:  2005-04-05     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  United States    
Other Details:
Languages:  eng     Pagination:  4247-53     Citation Subset:  IM    
Department of Biology, University of Utah, Salt Lake City, Utah 84112, USA.
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MeSH Terms
Amino Acid Sequence
Amino Acids / chemistry*
Biological Assay
Chromatography, High Pressure Liquid
Chymotrypsin / chemistry
Conotoxins / chemistry
Disulfides / chemistry
Endopeptidases / chemistry
Mass Spectrometry
Molecular Sequence Data
Muscles / metabolism
Oxygen / chemistry
Peptides / chemistry*
Phenylalanine / chemistry
Protein Conformation
Protein Folding
Protein Isoforms
Protein Processing, Post-Translational*
Protein Structure, Tertiary
Rana pipiens
Sequence Homology, Amino Acid
Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
Time Factors
Grant Support
Reg. No./Substance:
0/Amino Acids; 0/Conotoxins; 0/Disulfides; 0/Peptides; 0/Protein Isoforms; 63-91-2/Phenylalanine; 7782-44-7/Oxygen; EC 3.4.-/Endopeptidases; EC; EC 3.4.24.-/Metalloendopeptidases; EC Asp-N

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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