Peptidase M3 mitochondrial intermediate peptidase (MIP; EC 3.4.24.59) belongs to the widespread subfamily M3A, that shows similarity to Thimet oligopeptidase (TOP). It is one of three peptidases responsible for the proteolytic processing of both nuclear and mitochondrial encoded precursor polypeptides targeted to various subcompartments of the mitochondria. It cleaves intermediate-size proteins initially processed by mitochondrial processing peptidase (MPP) to yield a processing intermediate with a typical N-terminal octapeptide that is sequentially cleaved by MIP to mature-size protein. MIP cleaves precursor proteins of respiratory components, including subunits of the electron transport chain and tri-carboxylic acid cycle enzymes, and components of the mitochondrial genetic machinery, including ribosomal proteins, translation factors, and proteins required for mitochondrial DNA metabolism. It has been suggested that the human MIP (HMIP polypeptide (gene symbol MIPEP) may be one of the loci predicted to influence the clinical manifestations of Friedreich's ataxia (FRDA), an autosomal recessive neurodegenerative disease caused by the lack of human frataxin. These proteins are enriched in cysteine residues, two of which are highly conserved, suggesting their importance to stability as well as in formation of metal binding sites, thus playing a role in MIP activity.
Feature 1: metal binding site [ion binding site], 3 residue positions
Conserved feature residue pattern:H H E
Evidence:
Comment:generally in GluZincins a zinc ion is tetrahedrally co-ordinated by three amino acid ligands and a water molecule; Saccharomyces cerevisiae mitochondrial intermediate peptidase has been shown to bind Mn2+, but could also bind Mg2+ or Ca2+
Jiyao W et al.(2023). "The conserved domain database in 2023.",