Antimicrobial Susceptibility Pattern and Mutations of Outer Membrane Porin in Clinical Isolates Klebsiella pneumoniae

Nutrients usually cross the outer membrane of Escherichia coli by diffusion through water-filled channels surrounded by a specific class of protein, porins. In this study, the rates of diffusion of hydrophilic nonelectrolytes, mostly sugars and sugar alcohols, through the porin channels were determined in two systems, (a) vesicles reconstituted from phospholipids and purified porin and (b) inta...

TolB is a periplasmic protein of the cell envelope Tol complex. It is partially membrane associated through an interaction with the outer membrane lipoprotein PAL (peptidoglycan-associated lipoprotein), which also belongs to the Tol system. The interaction of TolB with outer membrane porins of Escherichia coli was investigated with a purified TolB derivative harboring a six-histidine tag. TolB ...

The porin Omp32 is the major outer membrane protein of the bacterium Delftia acidovorans. The crystal structures of the strongly anion-selective porin alone and in complex with the substrate malate were solved at 1.5 and 1.45 A resolution, respectively, and revealed a malate-binding motif adjacent to the channel constriction zone. Binding is mediated by interaction with a cluster of two arginin...

The role of positive charges located on the hydrophilic surface of the mitochondrial outer membrane channel was investigated by studying the interaction between LDAO-solubilized porin and a cation-exchanger column. The binding of porin to the column material was inhibited when the elution buffer had a pH of 9 or when 2 mM dextran sulfate was added to the buffer at neutral pH. Interestingly, the...

OmpF and OmpC porins were differentially regulated by nutrient limitation and growth rate in glucose- or nitrogen-limited chemostat cultures of Escherichia coli. Transcriptional and translational ompF fusions showed a sharp peak of expression under glucose limitation at D = 0.3 h-1, with lower amounts at lower and higher growth rates. The peak of OmpR-dependent transcriptional stimulation of om...