1.B.19 The Glucose-selective OprB Porin (OprB) Family

The OprB family of outer membrane porins includes proteins from α-, β-, γ- and δ-proteobacteria including species of Pseudomonas, Acinetobacter, Xanthomonas, Ralstonia, Bradyrhizobium, and other organisms including cyanobacteria, flavobacteria, planctomyces and chlamydia. Some of the Pseudomonas homologues have been reconstituted in proteoliposomes and characterized (Adewoye et al., 1998). The Km for glucose of the P. aeruginosa homologue is 4 μM. It exhibits high specificity for glucose, but also transports glycerol, mannitol and fructose (Wylie and Worobec, 1993). They have 40-50% β-structure. The oprB gene is adjacent to the gltK gene encoding an ATPase of a probable glucose ABC transporter. oprB expression is induced by glycerol and glucose limitation, repressed by salicylate, and responsive to temperature and pH (Adewoye and Worobec, 1999).

A second member of the family is OprB of Burkholderia pseudomallei (TC #1.B.19.1.2; Chan et al., 2007). This functions in conjunction with BpeAB (TC #2.A.6.2.23) to export several quorum sensing acyl homoserine lactones with acyl chains of 8-14 carbons.

This family belongs to the Outer Membrane Pore-forming Protein I (OMPP-I) Superfamily .



Adewoye, L.O. and E.A. Worobec. (2000). Identification and characterization of the gltK gene encoding a membrane-associated glucose transport protein of Pseudomonas aeruginosa. Gene 253: 323-330.

Adewoye, L.O. and E.A. Worobec. (1999). Multiple environmental factors regulate the expression of the carbohydrate-selective OprB porin of Pseudomonas aeruginosa. Can. J. Microbiol. 45: 1033-1042.

Adewoye, L.O., L. Tschetter, J. O'Neil, and E.A. Worobec. (1998). Channel specificity and secondary structure of the glucose-inducible porins of Pseudomonas spp. J. Bioenerg. Biomembr. 30: 257-267.

Bae, N., H.J. Park, H. Park, M. Kim, and S.W. Han. (2018). Deciphering the functions of the outer membrane porin OprBXo involved in virulence, motility, exopolysaccharide production, biofilm formation, and stress tolerance in Xanthomonas oryzae pv. oryzae. Mol Plant Pathol. [Epub: Ahead of Print]

Chan, Y.Y., H.S. Bian, T.M. Tan, M.E. Mattmann, G.D. Geske, J. Igarashi, T. Hatano, H. Suga, H.E. Blackwell, and K.L. Chua. (2007). Control of quorum sensing by a Burkholderia pseudomallei multidrug efflux pump. J. Bacteriol. 189: 4320-4324.

Ficarra, F.A., C. Grandellis, E.M. Galván, L. Ielpi, R. Feil, J.E. Lunn, N. Gottig, and J. Ottado. (2016). Xanthomonas citri subsp. citri requires the outer membrane porin OprB for maximal virulence and biofilm formation. Mol Plant Pathol. [Epub: Ahead of Print]

Saravolac, E.G., N.F. Taylor, R. Benz, and R.E. Hancock. (1991). Purification of glucose-inducible outer membrane protein OprB of Pseudomonas putida and reconstitution of glucose-specific pores. J. Bacteriol. 173: 4970-4976.

Shrivastava, R., B. Basu, A. Godbole, M.K. Mathew, S.K. Apte, and P.S. Phale. (2011). Repression of the glucose-inducible outer-membrane protein OprB during utilization of aromatic compounds and organic acids in Pseudomonas putida CSV86. Microbiology 157: 1531-1540.

van den Berg, B. (2012). Structural basis for outer membrane sugar uptake in pseudomonads. J. Biol. Chem. 287: 41044-41052.

Williams, S.G., J.A. Greenwood, and C.W. Jones. (1994). The effect of nutrient limitation on glycerol uptake and metabolism in continuous cultures of Pseudomonas aeruginosa. Microbiology 140: 2961-2969.

Wylie, J.L. and E.A. Worobec. (1993). Substrate specificity of the high-affinity glucose transport system of Pseudomonas aeruginosa. Can. J. Microbiol. 39: 722-725.

Wylie, J.L. and E.A. Worobec. (1994). Cloning and nucleotide sequence of the Pseudomonas aeruginosa glucose-selective OprB porin gene and distribution of OprB within the family Pseudomonadaceae. Eur. J. Biochem. 220: 505-512.


TC#NameOrganismal TypeExample

Cation-selective, glucose-inducible glucose-transporting porin (also transports glycerol, mannitol, fructose, maltose, pentoses, etc.) (Adewoye and Worobec 1999).

Gram-negative proteobacteria

OprB porin of Pseudomonas aeruginosa

1.B.19.1.2The quorum sensing acyl homoserine lactone porin, OprBGram-negative bacteriaOprB of Burkholderia pseudomallei (EBA45175)

Carbohydrate-selective porin OprB (Shrivastava et al., 2011).  The high resolution 3-d structure reveals a 16 β-TMS barrel with a constriction explaining the preference of this porin for monosaccharides over disaccharides (van den Berg 2012).

Gram-negative bacteria

OprB of Pseudomonas putida (B0KPQ1)


OprB homologue


OprB homologue of Prochlorococcus marinus (A2CB33)


OprB homologue


OprB homologue of Rhodomicrobium vannielii (E3I261)


OprB homologue 


OprB homologue of Planctoymyces maris (A6C291)


OprB homologue


OprB homologue of Rhodopirellula baltica


Putative porin OprB


OprB of Acidobacterium capsulatum


Porin of 425 aas, OprB, required for virulence and biofilm formation (Ficarra et al. 2016). It is a sugar-selective porin (Bae et al. 2018).

OprB of Xanthomonas citri pv. mangiferaeindicae