InterPro domain: IPR003111

This signature defines the N-terminal substrate-binding domain of the archael, bacterial and eukaryotic lon proteases, which are ATP-dependent serine peptidases belonging to the MEROPS peptidase family S16 (lon protease family, clan SF). In the eukaryotes the majority of the proteins are located in the mitochondrial matrix [ 1 , 2 ]. In yeast, Pim1, is located in the mitochondrial matrix, is required for mitochondrial function, is constitutively expressed but is increased after thermal stress, suggesting that Pim1 may play a role in the heat shock response [ 3 ].

This structure of this domain has been determined [ 4 , 5 , 6 ]. This domain also occurs in proteins which lack the peptidase domain, such as the SPBC14F5.10c gene product from Schizosaccharomyces pombe; these proteins are uncharacterized.

1. A human mitochondrial ATP-dependent protease that is highly homologous to bacterial Lon protease. Proc. Natl. Acad. Sci. U.S.A. 90, 11247-51
2. Maize contains a Lon protease gene that can partially complement a yeast pim1-deletion mutant. Plant Mol. Biol. 37, 141-54
3. PIM1 encodes a mitochondrial ATP-dependent protease that is required for mitochondrial function in the yeast Saccharomyces cerevisiae. J. Biol. Chem. 269, 238-42
4. Crystal structure of the N-terminal domain of E. coli Lon protease. Protein Sci. 14, 2895-900
5. Structural genomics reveals EVE as a new ASCH/PUA-related domain. Proteins 75, 760-73
6. Crystal structure of Lon protease: molecular architecture of gated entry to a sequestered degradation chamber. EMBO J. 29, 3520-30