1.B.4 The Brucella-Rhizobium Porin (BRP) Family

The porin proteins in the BRP family are found in the Agrobacterium, Bartonella, Brucella, Mesorhizobium and Rhizobium genuses and are likely to be found in other closely related genera. Brucella species have two homologous outer membrane porins, Omp2a and Omp2b, encoded by two closely linked genes oriented in oppostie directions. Omp2 proteins exist in many size variants due to multiple gene conversions between the two homologous genes that lead to chimeric proteins. These variants show different permeability to sugars as well as different ion conductivities (Paquet et al. 2001). This family is also called the Omp2 family in SwissProt.



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

 

References:

Cloeckaert, A., H.S. Debbarh, N. Vizcaino, E. Saman, G. Dubray, and M.S. Zygmunt. (1996). Cloning, nucleotide sequence, and expression of the Brucella melitensis bp26 gene coding for a protein immunogenic in infected sheep. FEMS Microbiol. Lett. 140: 139-144.

Cloeckaert, A., J.M. Verger, M. Grayon, and N. Vizcaino. (1996). Molecular and immunological characterization of the major outer membrane proteins of Brucella. FEMS Microbiol Lett. 145: 1-8.

Hohle, T.H., W.L. Franck, G. Stacey, and M.R. O'Brian. (2011). Bacterial outer membrane channel for divalent metal ion acquisition. Proc. Natl. Acad. Sci. USA 108: 15390-15395.

Jeanteur, D., J.H. Lakey, and F. Pattus. (1991). The bacterial porin superfamily: sequence alignment and structure prediction. Mol. Microbiol. 5: 2153-2164.

Jeanteur, D., J.H. Lakey, and F. Pattus. (1994). The porin superfamily: diversity and common features. In: Bacterial Cell Wall. Edited by Ghuysen, J.M., Hakenbeck, R. Elsevier, Amsterdam, pp. 363-380.

Nikaido, H. (1992). Porins and specific channels of bacterial outer membranes. Mol. Microbiol. 6: 435-442.

Paquet, J.Y., M.A. Diaz, S. Genevrois, M. Grayon, J.M. Verger, X. de Bolle, J.H. Lakey, J.J. Letesson, and A. Cloeckaert. (2001). Molecular, antigenic, and functional analyses of Omp2b porin size variants of Brucella spp. J. Bacteriol. 183: 4839-4847.

Paul, S., B.V. Peddayelachagiri, S. Nagaraj, J.J. Kingston, and H.V. Batra. (2018). Recombinant outer membrane protein 25c from Brucella abortus induces Th1 and Th2 mediated protection against Brucella abortus infection in mouse model. Mol Immunol 99: 9-18.

Schulz, G.E. (1996). Porins: general to specific, native to engineered passive pores. Curr. Opin. Struc. Biol. 6: 485-490.

Vizcaino, N., A. Cloeckaert, M.S. Zygmunt, and G. Dubray. (1996). Cloning, nucleotide sequence, and expression of the Brucella melitensis omp31 gene coding for an immunogenic major outer membrane protein. Infect Immun. 64: 3744-3751.

Examples:

TC#NameOrganismal TypeExample
1.B.4.1.1

Fusion porin protein of 1115 aas with two domains that are homologous to members of family 1.B.4 at the N- and C-termini of this protein and a central domain homologous to members of family 1.B.13 proteins. These fusion proteins are found in several closely related species of α-proteobacteria such as those in the genuses, Methylosinus and Methylocystis (BL Reddy and MH Saier, unpublished observations).

Proteobacteria

Fusion porin protein of Methylosinus trichosporium

 
1.B.4.1.2

Fusion porin protein of 840 aas with an N-terminal domain that is homologous to members of family 1.B.13, and a C-terminal domain that is homologous to members of family 1.B.4 proteins.  It is 60% identical to the last two domains in 1.B.4.2.15 but it lacks the N-terminal domain of that protein.

Proteobacteria

Fusion protein of Methylosinus trichosporium

 
Examples:

TC#NameOrganismal TypeExample
1.B.4.2.10

Hypothetical protein of 259 aas

Proteobacteria

HP of Coxiella burnetii

 
1.B.4.2.11

Putative porin of 200 aas

Proteobacteria

PP of Octadecabacter antarcticus

 
1.B.4.2.12

Putative porin of 233 aas

Proteobacteria

PP of Azorhizobium caulinodans

 
1.B.4.2.13

Porin of 240 aas

Proteobacteria

Porin of Brucella canis

 
1.B.4.2.14

Putative porin of 199 aas

Proteobacteria

PP of Octadecabacter antarcticus

 
1.B.4.2.15Outer membrane immunogenic protein, Omp31BacteriaOmp31 of Brucella melitensis (Q45322)
 
1.B.4.2.16

High affinity Mn2+ (but not Co2+ or Cu2+) porin, MnoP (675 aas) (Hohle et al., 2011).  This protein seems to be a fusion protein between an Omp_b-br1 family porin (N-terminus) and an OprB porin (C-terminus).  It shows little sequence similiarity with the OprB family proteins of 1.B.19.

Bacteria

MnoP of Bradyrhizobium japonicum (Q89Y60)

 
1.B.4.2.17

Opacity protein of 188 aas

Proteobacteria

Opacity protein of Sphingomonas witichii

 
1.B.4.2.18

Outer membrane porin, Omp25c, of 228 aas. The collective Th1 plus Th2 immune responses induced by Omp25c protects against Brucella infections (Paul et al. 2018).

Omp25c of Brucella abortus

 

 
1.B.4.2.2

Uncharacterized porin homologue of 242 aas.  Shows similarity with 9.B.184.1.1 which also shows similarity with members of 1.B.6; it is likely to be a porin.

Proteobacteria

Putative porin of Bradyrhizobium sp. ORS 285

 
1.B.4.2.3

Putative porin

α-Proteobacteria

Putative porin of Rhizobium sp. AP16

 
1.B.4.2.4

Putative porin

α-Proteobacteria

Putative porin of Bradyrhizobium japonicum

 
1.B.4.2.5

Putative porin of 252 aas

Proteobacteria

Porin of Bradyrhizobium sp.

 
1.B.4.2.6

Porin of 252 aas

Proteobacteria

Porin of Xanthobacter autotrophicus

 
1.B.4.2.7

Putative porin of 289 aas

Proteobacteria

Putative porin of Methylobacterium extorquens

 
1.B.4.2.8

Porin of 241 aas

Proteobacteria

Porin of Nitrobacter winogradskyi

 
1.B.4.2.9

Probable carbohydrate-selective outer membrane porin, OprB, of 302 aas (Brunen et al. 1991).

Proteobacteria

OMP of Acidovorax delafiedii

 
Examples:

TC#NameOrganismal TypeExample