1pci

PROCARICAINPROCARICAIN

Structural highlights 1pci is a 3 chain structure with sequence from Carica papaya. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 3.2Å Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function PAPA3_CARPA 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 PubMed BACKGROUND: Cysteine proteases are involved in a variety of cellular processes including cartilage degradation in arthritis, the progression of Alzheimer's disease and cancer invasion: these enzymes are therefore of immense biological importance. Caricain is the most basic of the cysteine proteases found in the latex of Carica papaya. It is a member of the papain superfamily and is homologous to other plant and animal cysteine proteases. Caricain is naturally expressed as an inactive zymogen called procaricain. The inactive form of the protease contains an inhibitory proregion which consists of an additional 106 N-terminal amino acids; the proregion is removed upon activation. RESULTS: The crystal structure of procaricain has been refined to 3.2 A resolution; the final model consists of three non-crystallographically related molecules. The proregion of caricain forms a separate globular domain which binds to the C-terminal domain of mature caricain. The proregion also contains an extended polypeptide chain which runs through the substrate-binding cleft, in the opposite direction to that of the substrate, and connects to the N terminus of the mature region. The mature region does not undergo any conformational change on activation. CONCLUSIONS: We conclude that the rate-limiting step in the in vitro activation of procaricain is the dissociation of the prodomain, which is then followed by proteolytic cleavage of the extended polypeptide chain of the proregion. The prodomain provides a stable scaffold which may facilitate the folding of the C-terminal lobe of procaricain. The prosequence of procaricain forms an alpha-helical domain that prevents access to the substrate-binding cleft.,Groves MR, Taylor MA, Scott M, Cummings NJ, Pickersgill RW, Jenkins JA Structure. 1996 Oct 15;4(10):1193-203. PMID:8939744 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

spinqualitylabelsall models 1pci, resolution 3.20Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image