Download MendeleyBacteriocin as-48, a Microbial Cyclic Polypeptide Structurally and Functionally Related to Mammalian Nk-Lysin
Gonzalez, C., Langdon, G., Bruix, M., Galvez, A., Valdivia, E., Maqueda, M., Rico, M.(2000) Proc Natl Acad Sci U S A 97: 11221
- PubMed: 11005847
- DOI: https://doi.org/10.1073/pnas.210301097
- Primary Citation of Related Structures:
1E68 - PubMed Abstract:
The solution structure of bacteriocin AS-48, a 70-residue cyclic polypeptide from Enterococcus faecalis, consists of a globular arrangement of five alpha-helices enclosing a compact hydrophobic core. The head-to-tail union lies in the middle of helix 5, a fact that is shown to have a pronounced effect on the stability of the three-dimensional structure. Positive charges in the side chains of residues in helix 4 and in the turn linking helix 4 to helix 5 form a cluster that most probably determine its antibacterial activity by promoting pore formation in cell membranes. A similar five-helix structural motif has been found in the antimicrobial NK-lysin, an effector polypeptide of T and natural killer (NK) cells. Bacteriocin AS-48 lacks the three disulfide bridges characteristic of the saposin fold present in NK-lysin, and has no sequence homology with it. Nevertheless, the similar molecular architecture and high positive charge strongly suggest a common mechanism of antibacterial action.
Organizational Affiliation:
Instituto de Estructura de la Materia, Consejo Superior de Investigaciones Cientificas, Madrid 28006, Spain.
