Structural and Functional Roles of the Surface-Exposed Loops of the β-Barrel Membrane Protein OmpA from Escherichia coli - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of Bacteriology Année : 1999

Structural and Functional Roles of the Surface-Exposed Loops of the β-Barrel Membrane Protein OmpA from Escherichia coli

Résumé

The N-terminal domain of the OmpA protein from Escherichia coli , consisting of 170 amino acid residues, is embedded in the outer membrane, in the form of an antiparallel β-barrel whose eight transmembrane β-strands are connected by three short periplasmic turns and four relatively large surface-exposed hydrophilic loops. This protein domain serves as a paradigm for the study of membrane assembly of integral β-structured membrane proteins. In order to dissect the structural and functional roles of the surface-exposed loops, they were shortened separately and in all possible combinations. All 16 loop deletion mutants assembled into the outer membrane with high efficiency and adopted the wild-type membrane topology. This systematic approach proves the absence of topogenic signals (e.g., in the form of loop sizes or charge distributions) in these loops. The shortening of surface-exposed loops did not reduce the thermal stability of the protein. However, none of the mutant proteins, with the exception of the variant with the fourth loop shortened, served as a receptor for the OmpA-specific bacteriophage K3. Furthermore, all loops were necessary for the OmpA protein to function in the stabilization of mating aggregates during F conjugation. An OmpA deletion variant with all four loops shortened, consisting of only 135 amino acid residues, constitutes the smallest β-structured integral membrane protein known to date. These results represent a further step toward the development of artificial outer membrane proteins.

Dates et versions

hal-03621334 , version 1 (28-03-2022)

Identifiants

Citer

Ralf Koebnik. Structural and Functional Roles of the Surface-Exposed Loops of the β-Barrel Membrane Protein OmpA from Escherichia coli. Journal of Bacteriology, 1999, 181 (12), pp.3688-3694. ⟨10.1128/JB.181.12.3688-3694.1999⟩. ⟨hal-03621334⟩
5 Consultations
0 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More