Lateral diffusion of proteins in the periplasm of Escherichia coli.

AUTOR(ES)

Brass, J M

RESUMO

We have introduced biologically active, fluorescently labeled maltose-binding protein into the periplasmic space of Escherichia coli and measured its lateral diffusion coefficient by the fluorescence photobleaching recovery method. Diffusion of this protein in the periplasm was found to be surprisingly low (lateral diffusion coefficient, 0.9 X 10(-10) cm2 s-1), about 1,000-fold lower than would be expected for diffusion in aqueous medium and almost 100-fold lower than for an equivalent-size protein in the cytoplasm. Galactose-binding protein, myoglobin, and cytochrome c were also introduced into the periplasm and had diffusion coefficients identical to that determined for the maltose-binding protein. For all proteins nearly 100% recovery of fluorescence was obtained after photobleaching, indicating that the periplasm is a single contiguous compartment surrounding the cell. These data have considerable implications for periplasmic structure and for the role of periplasmic proteins in transport and chemotaxis.

Documentos Relacionados

• Role of domain II of Pseudomonas exotoxin in the secretion of proteins into the periplasm and medium by Escherichia coli.
• Role for membrane potential in the secretion of protein into the periplasm of Escherichia coli.
• Effects of signal sequence mutations on the kinetics of alkaline phosphatase export to the periplasm in Escherichia coli.
• Diffusion of aminoglycoside antibiotics across the outer membrane of Escherichia coli.
• Translational control of exported proteins in Escherichia coli.