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.
PDB ID: 1GFNDownload
MMDB ID: 56224
PDB Deposition Date: 1996/5/8
Updated in MMDB: 2012/10
Experimental Method:
x-ray diffraction
Resolution: 3.1  Å
Source Organism:
Similar Structures:
Biological Unit for 1GFN: trimeric; determined by author and by software (PISA,PQS)
Molecular Components in 1GFN
Label Count Molecule
Proteins (3 molecules)
Matrix Porin Outer Membrane Protein F(Gene symbol: ompF)
Molecule annotation
Chemicals (27 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB