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The Carbohydrate-selective porin (OprB) Family [Function: Specific diffusion channels] Seed alignment | Full alignment | Pfam page | TC-DB page

The OprB family includes the Pseudomonas aeruginosa porin B (OprB), a substrate-selective channel for a variety of different sugars, which is probably restricted to carbohydrates and facilitates glucose fusion across the outer membrane. Homologs are also found in Pseudomonas chlororaphis, Burkholderia cepacia, Pseudomonas fluorescens, Acinetobacter calcoaceticus and Xanthomonas campestris. The high-affinity glucose transport system is primarily specific for glucose and well conserved, although the outer membrane components may differ in channel architecture and specificity for other carbohydrates. OprB forms a monomeric, 16-stranded ß-barrel with a constriction formed by extracellular loops L2 and L3. The side chains of two highly conserved arginine residues (Arg(83) and Arg(110)) and a conserved glutamate (Glu(106)) line the channel constriction and interact with a bound glucose molecule.

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Literature references

Structural basis for outer membrane sugar uptake in pseudomonads
J Biol Chem. 2012 Nov 30;287(49):41044-52. doi: 10.1074/jbc.M112.408518. Epub 2012 Oct 12.
PMID: 23066028

Multiple environmental factors regulate the expression of the carbohydrate-selective OprB porin of Pseudomonas aeruginosa
Can J Microbiol. 1999 Dec;45(12):1033-42.
PMID: 10696483

Channel specificity and secondary structure of the glucose-inducible porins of Pseudomonas spp
J Bioenerg Biomembr. 1998 Jun;30(3):257-67. doi: 10.1023/a:1020596820314.
PMID: 9733092

The OprB porin plays a central role in carbohydrate uptake in Pseudomonas aeruginosa
J Bacteriol. 1995 Jun;177(11):3021-6. doi: 10.1128/jb.177.11.3021-3026.1995.
PMID: 7768797

Cloning and nucleotide sequence of the Pseudomonas aeruginosa glucose-selective OprB porin gene and distribution of OprB within the family Pseudomonadaceae
Eur J Biochem. 1994 Mar 1;220(2):505-12. doi: 10.1111/j.1432-1033.1994.tb18649.x.
PMID: 8125108

Proteins in this family with 3D-structure
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