1lop

From Proteopedia

Jump to: navigation, search


1lop, resolution 1.80Å ()
Non-Standard Residues: ,
Activity: Peptidylprolyl isomerase, with EC number 5.2.1.8
Resources: FirstGlance, OCA, PDBsum, RCSB
Coordinates: save as pdb, mmCIF, xml



Contents

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

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.

About this Structure

1lop is a 2 chain structure with sequence from Escherichia coli. Full crystallographic information is available from OCA.

See Also

Reference

  • Konno M, Ito M, Hayano T, Takahashi N. The substrate-binding site in Escherichia coli cyclophilin A preferably recognizes a cis-proline isomer or a highly distorted form of the trans isomer. J Mol Biol. 1996 Mar 15;256(5):897-908. PMID:8601841
  • Sandelin E. On hydrophobicity and conformational specificity in proteins. Biophys J. 2004 Jan;86(1 Pt 1):23-30. PMID:14695246 doi:10.1016/S0006-3495(04)74080-1

Proteopedia Page Contributors and Editors (what is this?)

OCA

Personal tools