| Gram-negative porin | |||||||||
|---|---|---|---|---|---|---|---|---|---|
 | |||||||||
| Identifiers | |||||||||
| Symbol | Porin_1 | ||||||||
| Pfam | PF00267 | ||||||||
| Pfam clan | CL0193 | ||||||||
| InterPro | IPR001702 | ||||||||
| PROSITE | PDOC00498 | ||||||||
| SCOP2 | 1mpf / SCOPe / SUPFAM | ||||||||
| TCDB | 1.B.1 | ||||||||
| OPM superfamily | 31 | ||||||||
| OPM protein | 1pho | ||||||||
| CDD | cd01345 | ||||||||
| |||||||||
General bacterial porins are a family of porin proteins from the outer membranes of Gram-negative bacteria. The porins act as molecular filters for hydrophilic compounds.[1] They are responsible for the 'molecular sieve' properties of the outer membrane. Porins form large water-filled channels which allow the diffusion of hydrophilic molecules into the periplasmic space. Some porins form general diffusion channels that allow any solute up to a certain size (that size is known as the exclusion limit) to cross the membrane, while other porins are specific for one particular solute and contain a binding site for that solute inside the pores (these are known as selective porins). As porins are the major outer membrane proteins, they also serve as receptor sites for the binding of phages and bacteriocins.
General diffusion porins usually assemble as a trimer in the membrane, and the transmembrane core of these proteins is composed exclusively of beta strands.[2] It has been shown[3] that a number of porins are evolutionarily related.
- ^ Benz R, Bauer K (1988). "Permeation of hydrophilic molecules through the outer membrane of gram-negative bacteria. Review on bacterial porins". Eur. J. Biochem. 176 (1): 1–19. doi:10.1111/j.1432-1033.1988.tb14245.x. PMID 2901351.
- ^ Jap BK, Walian PJ (1990). "Biophysics of the structure and function of porins". Q. Rev. Biophys. 23 (4): 367–403. doi:10.1017/S003358350000559X. PMID 2178269.
- ^ Pattus F, Jeanteur D, Lakey JH (1991). "The bacterial porin superfamily: sequence alignment and structure prediction". Mol. Microbiol. 5 (9): 2153–2164. doi:10.1111/j.1365-2958.1991.tb02145.x. PMID 1662760. S2CID 29688606.