4cms | pdb_00004cms

X-RAY ANALYSES OF ASPARTIC PROTEINASES IV. STRUCTURE AND REFINEMENT AT 2.2 ANGSTROMS RESOLUTION OF BOVINE CHYMOSIN

spinqualitylabelsall models 4cms, resolution 2.20Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4cms is a 1 chain structure with sequence from Bovin. The December 2000 RCSB PDB Molecule of the Month feature on Pepsin by David S. Goodsell is 10.2210/rcsb_pdb/mom_2000_12. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Activity: Chymosin, with EC number 3.4.23.4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum Function [CHYM_BOVIN] Chymosin is synthesized in the mucosa of the abomasum (fourth stomach) of young (unweaned) ruminants. The enzyme hydrolyzes casein to paracasein. 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 The structure of calf chymosin (EC 3.4.23.3), the aspartic proteinase from the gastric mucosa, was solved using the technique of molecular replacement. We describe the use of different search models based on distantly related fungal aspartic proteinases and investigate the effect of using only structurally conserved regions. The structure has been refined to a crystallographic R-factor of 17% at 2.2 A resolution with an estimated co-ordinate error of 0.21 A. In all, 136 water molecules have been located of which eight are internal. The structure of chymosin resembles that of pepsin and other aspartic proteinases. However, there is a considerable rearrangement of the active-site "flap" and, in particular, Tyr75 (pepsin numbering), which forms part of the specificity pockets S1 and S1'. This is probably a consequence of crystal packing. Electrostatic interactions on the edge of the substrate binding cleft appear to account for the restricted proteolysis of the natural substrate kappa-casein by chymosin. The local environment of invariant residues is examined, showing that structural constraints and side-chain hydrogen bonding can play an important role in the conservation of particular amino acids. X-ray analyses of aspartic proteinases. IV. Structure and refinement at 2.2 A resolution of bovine chymosin.,Newman M, Safro M, Frazao C, Khan G, Zdanov A, Tickle IJ, Blundell TL, Andreeva N J Mol Biol. 1991 Oct 20;221(4):1295-309. PMID:1942052 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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