Investigation of the substrate specificity of lacticin 481 synthetase by using nonproteinogenic amino acids.

Abstract

Lantibiotics are peptide antimicrobial compounds that are characterized by the thioether-bridged amino acids lanthionine and methyllanthionine. For lacticin 481, these structures are installed in a two-step post-translational modification process by a bifunctional enzyme, lacticin 481 synthetase (LctM). LctM catalyzes the dehydration of Ser and Thr residues to generate dehydroalanine or dehydrobutyrine, respectively, and the subsequent intramolecular regio- and stereospecific Michael-type addition of cysteines onto the dehydroamino acids. In this study, semisynthetic substrates containing nonproteinogenic amino acids were prepared by expressed protein ligation and [3+2]-cycloaddition of azide and alkyne-functionalized peptides. LctM demonstrated broad substrate specificity toward substrates containing beta-amino acids, D-amino acids, and N-alkyl amino acids (peptoids) in certain regions of its peptide substrate. These findings showcase its promise for use in lantibiotic and peptide-engineering applications, whereby nonproteinogenic amino acids might impart improved stability or modulated biological activities. Furthermore, LctM permitted the incorporation of an alkyne-containing amino acid that can be utilized for the site-selective modification of mature lantibiotics and used in target identification.

• Authors: Matthew R Levengood, Christopher C Kerwood, Champak Chatterjee, Wilfred A van der Donk
• Journal: Chembiochem : a European journal of chemical biology (Chembiochem) Vol. 10 Issue 5 Pg. 911-9 (Mar 23 2009) ISSN: 1439-7633 [Electronic] Germany
• PMID: 19222036 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• Amino Acids
• Anti-Bacterial Agents
• Bacteriocins
• Enzymes
• LctM protein, Lactococcus lactis
• Peptides
• lacticin 481

Topics

• Amino Acid Sequence
• Amino Acids (chemistry, metabolism)
• Anti-Bacterial Agents (metabolism)
• Bacteriocins (metabolism)
• Enzymes (metabolism)
• Molecular Sequence Data
• Molecular Structure
• Peptides (chemistry, genetics, metabolism)
• Protein Processing, Post-Translational
• Sequence Alignment
• Substrate Specificity