Primary structure of major outer membrane protein II (ompA protein) of Escherichia coli K-12.

Abstract

The amino acid sequence of major outer membrane protein II* (ompA protein) from Escherichia coli K-12 has been determined. The transmembrane polypeptide consists of 325 residues, resulting in a molecular weight of 35,159. The transmembrane part of the protein is located between residues 1 and 177. In Mis part of te rotein a predominantly lipophilic 27-residue segment exists that perhaps spans the membrane in a mostly a-helical conformation, or a 19-residue stretch of this segment might traverse the membrane linearly. Inside the outer membrane a sequence -Ala-Pro-AlaPro-Ala-Pro-Ala-Pro-exists that, analogous to the -Cys-Pro-ProCys-Pro-sequence in the hinge region of immunoglobulin, could assume the conformation of a polyproline helix. Computer analysis did not reveal a clear overall pattern of internal homology in the protein; besides the -Ala-Pro-repeat, only one local area (two adjacent dodeca eptide segments) shows some repetitiveness. The same analysis did not produce evidence for internal homology in the previously determined sequence of outer membrane protein I (porin) nor was any marked resemblance detected between transmembrane proteins I and II*.

The Amino Terminus of Pseudomonas aeruginosa Outer Membrane Protein OprF Forms Channels in Lipid Bilayer Membranes: Correlation with a Three-Dimensional Model

“…A somewhat analogous structure has been proposed for the Escherichia coli outer membrane protein OmpA (5,12,18), and these proteins, which also share some functional similarities, are considered orthologs. Consistent with this concept, significant amino acid sequence similarity has been detected between OprF and OmpA, but only in their C-terminal domains (39% identity, 56% similarity).…”

PhoE protein pore of the outer membrane of Escherichia coli K12 is a particularly efficient channel for organic and inorganic phosphate

“…LamB protein functions as a pore with substrate specificity for maltose and maltodextrins [32]. Molecular weights of the relevant proteins are between 47000 (for LamB protein) [33] and 35000 (for OmpA protein) [34].…”

Suppression by the ColV, I-K94 Plasmid of a Growth Lesion in ompA Mutants of Escherichia coli

“…Of these, about 148, at the C terminal region, protrude inwards into the periplasmic space (Chen et al, 1980). A loop (at residues about 60-70) appears to protrude to the outside (Cole et al, 1983); it is possible that about 70 N terminal residues protrude, since this segment becomes sensitive to proteolytic enzymes in one ompA mutant (Cole et al, 1983).…”

“…The OmpA protein is a transmembrane protein of 325 amino acids (Chen et al, 1980). Of these, about 148, at the C terminal region, protrude inwards into the periplasmic space (Chen et al, 1980).…”