Three-dimensional structure of leucocin A in trifluoroethanol and dodecylphosphocholine micelles: spatial location of residues critical for biological activity in type IIa bacteriocins from lactic acid bacteria.
Primary Citation of Related Structures: 2LEU, 3LEU
PubMed Abstract:
The first three-dimensional structure of a type IIa bacteriocin from lactic acid bacteria is reported. Complete 1H resonance assignments of leucocin A, a 37 amino acid antimicrobial peptide isolated from the lactic acid bacterium Leuconostoc gelidum UAL187, were determined in 90% trifluoroethanol (TFE)-water and in aqueous dodecylphosphocholine (DPC) micelles (1:40 ratio of leucocin A:DPC) using two-dimensional NMR techniques (e ...
The first three-dimensional structure of a type IIa bacteriocin from lactic acid bacteria is reported. Complete 1H resonance assignments of leucocin A, a 37 amino acid antimicrobial peptide isolated from the lactic acid bacterium Leuconostoc gelidum UAL187, were determined in 90% trifluoroethanol (TFE)-water and in aqueous dodecylphosphocholine (DPC) micelles (1:40 ratio of leucocin A:DPC) using two-dimensional NMR techniques (e.g., DQF-COSY, TOCSY, NOESY). Circular dichroism spectra, NMR chemical shift indices, amide hydrogen exchange rates, and long-range nuclear Overhauser effects indicate that leucocin A adopts a reasonably well defined structure in both TFE and DPC micelle environments but exists as a random coil in water or aqueous DMSO. Distance geometry and simulated annealing calculations were employed to generate structures for leucocin A in both lipophilic media. While some differences were noted between the structures calculated for the two different solvent systems, in both, the region encompassing residues 17-31 assumes an essentially identical amphiphilic alpha-helix conformation. A three-strand antiparallel beta-sheet domain (residues 2-16), anchored by the disulfide bridge, is also observed in both media. In TFE, these two regions have a more defined relationship relative to each other, while, in DPC micelles, the C-terminus is folded back onto the alpha-helix. The implications of these structural features with regard to the antimicrobial mechanism of action and target recognition are discussed.
Related Citations:
Molecular Characterization of Genes Involved in the Production of the Bacteriocin Leucocin a from Leuconostoc Gelidum Van Belkum, M.J., Stiles, M.E. (1995) Appl Environ Microbiol 61: 3573
15N-and 13C-Labeled Media from Anabaena Sp. For Universal Isotopic Labeling of Bacteriocins: NMR Resonance Assignments of Leucocin a from Leuconostoc Gelidum and Nisin a from Lactococcus Lactis Sailer, M., Helms, G.L., Henkel, T., Niemczura, W.P., Stiles, M.E., Vederas, J.C. (1993) Biochemistry 32: 310
NMR Assignment of Leucocin A, a Bacteriocin from Leuconostoc Gelidum, Supported by a Stable Isotope Labeling Technique for Peptides and Proteins Henkel, T., Sailer, M., Helms, G.L., Stiles, M.E., Vederas, J.C. (1992) J Am Chem Soc 114: 1898
Characterization of Leucocin A-Ual 187 and Cloning of the Bacteriocin Gene from Leuconostoc Gelidum Hastings, J.W., Sailer, M., Johnson, K., Roy, K.L., Vederas, J.C., Stiles, M.E. (1991) J Bacteriol 173: 7491
Organizational Affiliation:
Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2G2.
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