| Primary Identifier | IPR059192 | Type | Family |
| Short Name | PIN_19 |
| description | This entry represents uncharacterised PIN domain-containing proteins in bacteria. PIN-like domains can be classified into distinct groups; this subgroup corresponds to PIN_19, they belong to the VapC-like nucleases [].The PIN domain-like superfamily comprises five major structural groups of nucleases that share a common Rossmann-like fold consisting of a central five-stranded parallel ��-sheet but differ significantly in their structural elaborations and functions. The FEN-like nucleases (Group 1) possess the most complex architecture with additional elements like a "helical arch"and "hydrophobic wedge,"utilising 6-7 acidic residues to coordinate two metal ions for structure-specific 5' nuclease activity in DNA replication and repair. VapC-like nucleases (Group 2) represent a stripped-down version with a minimal H2' helical insert and 3-5 active site residues, functioning primarily as endoribonucleases in prokaryotic toxin-antitoxin systems targeting specific RNA structures. NYN-like nucleases (Group 3) lack the helical insert after ��-strand 2, resulting in an exposed active site with four acidic residues predicted to coordinate one metal ion, though their catalytic mechanism remains experimentally uncharacterised. PRORP domains (Group 4) feature unique bent helices and an extended ��-sheet with 4-5 aspartates coordinating two metal ions, functioning as proteinaceous RNase P enzymes for 5' tRNA maturation in eukaryotic organelles. Mut7-C-like domains (Group 5) represent the most divergent group, lacking core elements ��-helix 3 and ��-strand 3, with reduced active site conservation and a C-terminal zinc ribbon insertion, showing variable nuclease activity that appears species-dependent []. |
