LIS - Legume Information System
Information about legume traits for crop improvement
CicerMine
v5.1.0.3
Cicer data from the Legume Information System
v5.1.0.3
Cicer data from the Legume Information System
| Type | Homologous_superfamily |
| Description | This entry represents S-adenosyl-L-methionine-dependent methyltransferases (SAM MTase). Methyltransferases transfer a methyl group from a donor to an acceptor. SAM-binding methyltransferases utilise the ubiquitous methyl donor SAM as a cofactor to methylate proteins, small molecules, lipids, and nucleic acids. All SAM MTases contain a structurally conserved SAM-binding domain consisting of a central seven-stranded β-sheet that is flanked by three α-helices per side of the sheet [ ].A review published in 2003 [ ] divides all methyltransferases into 5 classes based on the structure of their catalytic domain (fold):class I: Rossmann-like α/βclass II: TIM β/α-barrel α/βclass III: tetrapyrrole methylase α/βclass IV: SPOUT α/β class V: SET domain all β Another paper [ ] based on a study of the Saccharomyces cerevisiae methyltransferome argues for four more folds:class VI: transmembrane all-α class VII: DNA/RNA-binding 3-helical bundle all-αclass VIII: SSo0622-like α+βclass IX: thymidylate synthetase α+βThe vast majority of methyltransferases belong to the Rossmann-like fold (Class I) which consists in a seven-stranded β-sheet adjoined by α-helices. The β-sheet contains a central topological switch-point resulting in a deep cleft in which SAM binds. Class I methyltransferases display two conserved positions, the first one is a GxGxG motif (or at least a GxG motif) at the end of the first β-strand which is characteristic of a nucleotide-binding site and is hence used to bind the adenosyl part of SAM, the second conserved position is an acidic residue at the end of the second β-strand that forms one hydrogen bond to each hydroxyl of the SAM ribose part. The core of these enzymes is composed by about 150 amino acids that show very strong spatial conservation [ ]. |
| Short Name | SAM-dependent_MTases_sf |
