2bl8: Difference between revisions

Many Gram-positive bacteria produce ribosomally synthesized antimicrobial, peptides, often termed bacteriocins. Genes encoding pediocin-like, bacteriocins are generally cotranscribed with or in close vicinity to a, gene encoding a cognate immunity protein that protects the, bacteriocin-producer from their own bacteriocin. We present the first, crystal structure of a pediocin-like immunity protein, EntA-im, conferring, immunity to the bacteriocin enterocin A. Determination of the structure of, this 103-amino acid protein revealed that it folds into an antiparallel, four-helix bundle with a flexible C-terminal part. The fact that the, immunity protein conferring immunity to carnobacteriocin B2 also consists, of a four-helix bundle (Sprules, T., Kawulka, K. E., and Vederas, J. C., (2004) Biochemistry 43, 11740-11749) strongly indicates that this is a, conserved structural motif in all pediocin-like immunity proteins. The, C-terminal half of the immunity protein contains a region that recognizes, the C-terminal half of the cognate bacteriocin, and the flexibility in the, C-terminal end of the immunity protein might thus be an important, characteristic that enables the immunity protein to interact with its, cognate bacteriocin. By homology modeling of three other pediocin-like, immunity proteins and calculation of the surface charge distribution for, EntA-im and the three structure models, different charge distributions, were observed. The differences in the latter part of helix 3, the, beginning of helix 4, and the loop connecting these helices might also be, of importance in determining the specificity.

2BL8 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Enterococcus_faecium Enterococcus faecium] with FLC as [http://en.wikipedia.org/wiki/ligand ligand]. Structure known Active Site: AC1. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=2BL8 OCA].  

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