LamB

• PFAM accession number: PF02264
• Interpro abstract (IPR003192):

  Maltoporin (LamB protein) forms a trimeric structure which facilitates the diffusion of maltodextrins across the outer membrane of Gram-negative bacteria. The membrane channel is formed by an antiparallel beta-barrel [ (PUBMED:7824948) ]. Loop 3 folds into the core to constrict pore size. Long irregular loops are found on the extracelllular side, while short turns are in the periplasm. Tightly-bound water molecules are found in the eyelet of the passage, and only substrates that can displace and replace the broken hydrogen bonds are likely to enter the pore. Loops 4, 6, and 9 have the greatest mobility and are highly variable; these are postulated to attract maltodextrins [ (PUBMED:9102468) ].

  The porin LamB family also includes porin BglH, which may be a sugar porin with a broad carbohydrate specificity, and sucrose porin [ (PUBMED:1649946) (PUBMED:9437428) ].

• GO process: carbohydrate transmembrane transport (GO:0034219)
• GO component: membrane (GO:0016020)
• GO function: porin activity (GO:0015288)

This is a PFAM domain. For full annotation and more information, please see the PFAM entry LamB