| Type: | Family | Name: | Methylthioribose-1-phosphate isomerase |
| Description: | This family contains proteins designated as 5-methylthioribose-1-phosphate isomerase (MTNA, , []). It also contains putative translation initiation factor 2B subunit proteins.5-methylthioribose-1-phosphate isomerase (MTNA) participates in the methionine salvage pathway catalysing the isomerisation of 5-methylthioribose-1-phosphate to 5-methylthio ribulose-1-phosphate []. The methionine salvage pathway leads to the synthesis of methionine from methylthioadenosine, the end product of the spermidine and spermine anabolism in many species.The delineation of this family is based in part on a discussion and neighbour-joining phylogenetic study [, ], of archaeal and other proteins homologous to the alpha, beta, and delta subunits of eukaryotic initiation factor 2B (eIF-2B), a five-subunit molecule that catalyzes GTP recycling for eIF-2. The archaeal proteins are related to the common ancestor of eIF-2B alpha, beta, and delta rather then specifically to any one of them, and that designation of particular archaeal members as corresponding to eIF-2B alpha or eIF-2B delta is imprecise. It has been suggested that designating the archaeal proteins as translation initiation factors remains unproven. | Short Name: | IF-M1Pi |
