1gfn

Publication Abstract from PubMed

OmpF porin is a nonspecific pore protein from the outer membrane of Escherichia coli. Previously, a set of mutants was selected that allow the passage of long maltodextrins that do not translocate through the wild-type pore. Here, we describe the crystal structures of four point mutants and one deletion mutant from this set; their functional characterization is reported in the accompanying paper (Saint, N., Lou, K.-L., Widmer, C., Luckey, M., Schirmer, T., Rosenbusch, J. P. (1996) J. Biol. Chem. 271, 20676-20680). All mutations have a local effect on the structure of the pore constriction and result in a larger pore cross-section. Substitution of each of the three closely packed arginine residues at the pore constriction (Arg-42, Arg-82, and Arg-132) by shorter uncharged residues causes rearrangement of the adjacent basic residues. This demonstrates mutual stabilization of these residues in the wild-type porin. Deletion of six residues from the internal loop (Delta109-114) results in disorder of seven adjacent residues but does not alter the structure of the beta-barrel framework. Thus, the large hollow beta-barrel motif can be regarded as an autonomous structure.

Structural and functional characterization of OmpF porin mutants selected for larger pore size. I. Crystallographic analysis.,Lou KL, Saint N, Prilipov A, Rummel G, Benson SA, Rosenbusch JP, Schirmer T J Biol Chem. 1996 Aug 23;271(34):20669-75. PMID:8702816^[2]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.