HIV protease substrate conformation: modulation by cyclophilin A

FEBS Letters

Handschumacher, Robert E²  Armitage, Ian M¹  McCornack, Melissa A¹  Caserta, Carlo²  Kakalis, Lazaros T² 

[1] Department of Biochemistry, University of Minnesota, 4-225 Millard Hall, 435 Delaware Street, S.E., Minneapolis, MN 55455-0347, USA;Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA

关键词: HIV protease;    Cyclophilin A;    Cyclosporin A;    Saturation transfer;    Nuclear Overhauser effect;    Peptidyl-prolyl trans-cis isomerase;    gag polyprotein;    CsA;    cyclosporin A;    CyPA;    cyclophilin A;    CA;    capsid protein;    DQF-COSY;    double quantum-filtered correlation spectroscopy;    HIV-1;    human immunodeficiency virus type-1;    IN;    integrase;    KPi;    potassium phosphate;    MA;    matrix protein;    NC;    nucleocapsid protein;    NMR;    nuclear magnetic resonance;    NOE;    nuclear Overhauser effect;    NOESY;    nuclear Overhauser effect spectroscopy;    ppm;    parts per million;    PR;    protease;    RT;    reverse transcriptase;    T 1;    longitudinal relaxation time;    TPPI;    time-proportional phase incrementation;   

DOI  :  10.1016/S0014-5793(97)00974-5

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Cyclophilin A (CyPA), a cytosolic peptidyl-prolyl trans-cis isomerase can accelerate the trans-cis isomerization of Xxx-Pro peptide bonds. One- and two-dimensional ¹H-NMR spectroscopy were used to determine that the heptapeptide Ser-Gln-Asn-Tyr-Pro-Ile-Val, a model peptide of an HIV-1 protease cleavage site in the gag polyprotein of HIV-1, is a substrate for CyPA. Experiments revealed a slow exchange about the Tyr-Pro peptide bond with 30±5% in the cis conformation (pH 1–9). While the interconversion rate is too slow to measure by kinetic NMR methods in the absence of CyPA, these methods, saturation transfer and NOE experiments, established that CyPA enhanced the rate of trans-cis interconversion, a process inhibited by cyclosporin A (CsA). With a substrate:CyPA ratio of 40:1, an interconversion rate of 2.5 s⁻¹ at 25°C was observed.

【 授权许可】

Unknown