1lop

CYCLOPHILIN A COMPLEXED WITH SUCCINYL-ALA-PRO-ALA-P-NITROANILIDE

spinqualitylabelsall models 1lop, resolution 1.80Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1lop is a 2 chain structure with sequence from Escherichia coli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.8Å Ligands: NIT, SIN Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function PPIB_ECOLI PPIases accelerate the folding of proteins. It catalyzes the cis-trans isomerization of proline imidic peptide bonds in oligopeptides. 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 three-dimensional structure of Escherichia coli cytosolic cyclophilin A (CyPA) complexed with a tripeptide (succinyl-Ala-Pro-Ala-p-nitroanilide) was refined at 1.8 A resolution by the multiple isomorphous replacement method to a crystallographic R-factor of 17.6%. As in human CyPA, the peptide binding site in E. coli enzyme is in a cleft created on the surface of the upper sheet of two orthogonal beta-sheets. In this cleft, the walls of the hydrophobic pocket are formed by the side-chains of five non-polar residues, Phe48, Met49, Phe107, Leu108, and Try120, with Phe99 at the bottom. When the cis isomer of the tripeptide binds to the enzyme, a cis-proline ring is inserted into the hydrophobic pocket. Since the binding pocket of CyPAs are largely hydrophobic, the cis isomer of a peptide can be bound more firmly than the trans isomer. Distortion of the trans isomer could lead to better binding, but at an energetic cost of the distortion energy. At the periphery of the upper beta-sheet in E. coli CyPA, conformations of loops L1, L3, and L4 and the segment connecting alpha1 and beta3 with deletions or insertions against human CyPA differ significantly from those in human CyPA. The refined model also shows that steric hindrance to attachment of cyclosporin A (CsA) prevents E. coli CyPA forming a complex with CsA. Thus, the extra amino acid residue of E. coli CyPA, polar Gln89, lies along the pathway to the hydrophobic pocket of CyPA and seems to prevent the access hydrophobic part of CsA to the cleft of CyPA. The substrate-binding site in Escherichia coli cyclophilin A preferably recognizes a cis-proline isomer or a highly distorted form of the trans isomer.,Konno M, Ito M, Hayano T, Takahashi N J Mol Biol. 1996 Mar 15;256(5):897-908. PMID:8601841 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Cyclophilin 3D structures

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