Protein Family Models

Members of this family are integral membrane proteins with 6 predicted transmembrane helices. Some members of this family have been shown to be essential for bacterial competence in uptake of extracellular DNA [1,4]. These proteins may transport DNA across the cell membrane. These proteins contain a highly conserved motif in the amino terminal transmembrane region that has two histidines that may form a metal binding site. [1]. 7934834. A novel determinant (comA) essential for natural transformation. competence in Neisseria gonorrhoeae and the effect of a comA. defect on pilin variation.. Facius D, Meyer TF;. Mol Microbiol 1993;10:699-712.. [2]. 7968523. Characterization of comE, a late competence operon of Bacillus. subtilis required for the binding and uptake of transforming. DNA.. Hahn J, Inamine G, Kozlov Y, Dubnau D;. Mol Microbiol 1993;10:99-111.. [3]. 8063112. Sequence of the rec-2 locus of Haemophilus influenzae:. homologies to comE-ORF3 of Bacillus subtilis and msbA of. Escherichia coli.. Clifton SW, McCarthy D, Roe BA;. Gene 1994;146:95-100.. [4]. 9573156. Isolation and characterization of three Streptococcus pneumoniae. transformation-specific loci by use of a lacZ reporter insertion. vector.. Pestova EV, Morrison DA;. J Bacteriol 1998;180:2701-2710. (from Pfam)

Date:

2024-08-14

Date:

2024-08-14

Apparant orthologs are found in 5 species so far (Haemophilus influenzae, Escherichia coli, Bacillus subtilis, Neisseria gonorrhoeae, Streptococcus pneumoniae), of which all but E. coli are model systems for the study of competence for natural transformation. This protein is a predicted multiple membrane-spanning protein likely to be involved in DNA internalization. In a large number of bacterial species not known to exhibit competence, this protein is replaced by a half-length N-terminal homolog of unknown function, modelled by the related HMM ComEC_N-term. The role for this protein in species that are not naturally transformable is unknown.

Date:

2024-06-14

The related HMM ComEC_Rec2 (TIGR00361) describes a set of proteins of ~ 700-800 residues, one each from a number of different species, of which most can become competent for natural transformation with exogenous DNA. The best-studied examples are ComEC from Bacillus subtilis and Rec-2 from Haemophilus influenzae, where the protein appears to form part of the DNA import structure. This HMM represents a region found in full-length ComEC/Rec2 and shorter homologs of unknown function from large number of additional bacterial species, most of which are not known to become competent for transformation (an exception is Helicobacter pylori).

Date:

2019-09-10