1RMH

RECOMBINANT CYCLOPHILIN A FROM HUMAN T CELL

Summary for 1RMH

• Entry DOI: 10.2210/pdb1rmh/pdb
• Descriptor: CYCLOPHILIN A, AAPF PEPTIDE SUBSTRATE (3 entities in total)
• Functional Keywords: complex (isomerase-substrate), isomerase- isomerase substrate complex, isomerase/ isomerase substrate
• Biological source: Homo sapiens (human)
• Total number of polymer chains: 4
• Total formula weight: 37059.90

Authors

Zhao, Y.,Ke, H. (deposition date: 1995-07-31, release date: 1996-10-14, Last modification date: 2025-03-26)

Primary citation

Zhao, Y.,Ke, H.
Crystal structure implies that cyclophilin predominantly catalyzes the trans to cis isomerization.
Biochemistry, 35:7356-7361, 1996

PubMed Abstract: The crystal structure of human recombinant cyclophilin A complexed with a substrate of succinyl-Ala-Ala-Pro-Phe-p-nitroanilide (AAPF) has been determined and refined to an R-factor of 0.189 at 2.4 A resolution. The structure revealed only the cis form of the substrate bound to cyclophilin A in a stoichiometry of 1:1. This binding ratio is different from the structure of cyclophilin A complexed with the tetrapeptide N-acetyl-Ala-Ala-Pro-Ala-amidomethylcourmarin. Model docking revealed that the trans form of AAPF does not fit into the active site. The observation that only the trans cis form of AAPF binds to cyclophilin A implies that cyclophilin A predominantly catalyzes the trans to cis isomerization of a peptidylprolyl amide bond. On the basis of the structure, it is proposed that Arg55 hydrogen-bonds to the nitrogen to deconjugate the resonance of the prolyl amide bond and thus facilitates the cis-trans rotation.

PubMed: 8652511
DOI: 10.1021/bi9602775

Experimental method

X-RAY DIFFRACTION (2.4 Å)