InterPro

This entry contains proteins that belong to MEROPS peptidase family M24 (clan MG), which share a common structural-fold, the "pita-bread" fold. The fold contains both alpha helices and an anti-parallel beta sheet within two structurally similar domains that are thought to be derived from an ancient gene duplication. The active site, where conserved, is located between the two domains. The fold is common to methionine aminopeptidase (EC:3.4.11.18), aminopeptidase P (EC:3.4.11.9), prolidase (EC:3.4.13.9), agropine synthase and creatinase (EC:3.5.3.3). Though many of these peptidases require a divalent cation, creatinase is not a metal-dependent enzyme [PMID: 8146141, PMID: 12136144, PMID: 8471602].

The entry also contains proteins that have lost catalytic activity, for example Spt16, which is a component of the FACT complex. The crystal structure of the N-terminal domain of Spt16, determined to 2.1A, reveals an aminopeptidase P fold whose enzymatic activity has been lost. This fold binds directly to histones H3-H4 through a interaction with their globular core domains, as well as with their N-terminal tails [PMID: 18579787].

The FACT complex is a stable heterodimer in Saccharomyces cerevisiae (Baker's yeast) comprising Spt16p (P32558, IPR013953) and Pob3p (Q04636, IPR000969). The complex plays a role in transcription initiation and promotes binding of TATA-binding protein (TBP) to a TATA box in chromatin [PMID: 15987999]; it also facilitates RNA Polymerase II transcription elongation through nucleosomes by destabilising and then reassembling nucleosome structure [PMID: 12524332, PMID: 12934006, PMID: 18579787].