2fge
From Proteopedia
Crystal structure of presequence protease PreP from Arabidopsis thaliana
Structural highlights
Function[PREP1_ARATH] ATP-independent protease that degrades both mitochondrial and chloroplastic transit peptides after their cleavage. Also degrades other unstructured peptides. Specific for peptides in the range of 10 to 65 residues. Shows a preference for cleavage after small polar residues and before basic residues, with a bias for positively charged amino acid residues.[1] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedPresequence protease PreP is a novel protease that degrades targeting peptides as well as other unstructured peptides in both mitochondria and chloroplasts. The first structure of PreP from Arabidopsis thaliana refined at 2.1 Angstroms resolution shows how the 995-residue polypeptide forms a unique proteolytic chamber of more than 10,000 Angstroms(3) in which the active site resides. Although there is no visible opening to the chamber, a peptide is bound to the active site. The closed conformation places previously unidentified residues from the C-terminal domain at the active site, separated by almost 800 residues in sequence to active site residues located in the N-terminal domain. Based on the structure, a novel mechanism for proteolysis is proposed involving hinge-bending motions that cause the protease to open and close in response to substrate binding. In support of this model, cysteine double mutants designed to keep the chamber covalently locked show no activity under oxidizing conditions. The manner in which substrates are processed inside the chamber is reminiscent of the proteasome; therefore, we refer to this protein as a peptidasome. The closed structure of presequence protease PreP forms a unique 10,000 Angstroms3 chamber for proteolysis.,Johnson KA, Bhushan S, Stahl A, Hallberg BM, Frohn A, Glaser E, Eneqvist T EMBO J. 2006 May 3;25(9):1977-86. Epub 2006 Apr 6. PMID:16601675[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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