Protein Family Models

The alignments cover the most conserved region of the proteins, which is thought to be located in a cytoplasmic loop between two transmembrane domains. The members of this family have a variable number of transmembrane helices. (from Pfam)

Date:

2024-07-08

This HMM describes the permease protein, ModB, of the molybdate ABC transporter. This system has been characterized in E. coli [1], Staphylococcus carnosus [2] Rhodobacter capsulatus [3] and Azotobacter vinlandii [4]. Molybdate is chemically similar to sulfate, thiosulfate, and selenate. These related substrates, and sometimes molybdate itself, can be transported by the homologous sulfate receptor. Some apparent molybdenum transport operons include a permease related to this ModB, although less similar than some sulfate permease proteins and not included in this model.

Gene:

modB

Date:

2022-10-11

This model describes a clade of ABC porter genes with relatively weak homology compared to its neighbor clades, the molybdate (TIGR02141) and sulfate (TIGR00969) porters. Neighbor-Joining, PAM-distance phylogenetic trees support the separation of the clades in this way. Included in this group is a gene designated NifC in Clostridium pasturianum [1]. It would be reasonable to presume that NifC acts as a molybdate porter since the most common form of nitrogenase is a molybdoenzyme. Several other sequences falling within the scope of this model are annotated as molybdate porters and one, from Halobacterium, is annotated as a sulfate porter. There is presently no experimental evidence to support annotations with this degree of specificity.

Date:

2024-06-14