Question

Describe the role of porins and TonB-dependent receptors in gram negative bacteria. Answer should be in the form of a short paragraph.

Answer 1

Porins are proteins from outer membrane of gram negative bacteria. These porins act as molecular filters for hydrophilic compounds.

Porins are responsible for the seive properties of outer membrane.

Porins forms water filled channels that allows the diffusion of molecules of solute upto a certain size. They also serves as receptor site for binding of phages and bacteriocins.

TonB dependent receptor are beta barrel proteins. They sense signals from outside of bacterial cells and transmit into cytoplasm.

TonB dependent receptor in gram negative bacteria are associated with the uptake and transport of large substrates such as vitamin B12 and iron siderophore complex.