2LEU

HIGH RESOLUTION 1H NMR STUDY OF LEUCOCIN A IN 90% AQUEOUS TRIFLUOROETHANOL (TFE) (0.1% TFA), 18 STRUCTURES

Summary for 2LEU

• Entry DOI: 10.2210/pdb2leu/pdb
• Descriptor: LEUCOCIN A (1 entity in total)
• Functional Keywords: antibacterial peptide, bacteriocin
• Biological source: Leuconostoc gelidum
• Cellular location: Secreted: P34034
• Total number of polymer chains: 1
• Total formula weight: 3937.32

Authors

Gallagher, N.L.F.,Sailer, M.,Niemczura, W.P.,Nakashima, T.T.,Stiles, M.E.,Vederas, J.C. (deposition date: 1997-05-20, release date: 1997-11-26, Last modification date: 2024-11-06)

Primary citation

Fregeau Gallagher, N.L.,Sailer, M.,Niemczura, W.P.,Nakashima, T.T.,Stiles, M.E.,Vederas, J.C.
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.
Biochemistry, 36:15062-15072, 1997

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.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.

PubMed: 9398233
DOI: 10.1021/bi971263h

Experimental method

SOLUTION NMR