R73A and H144Q mutants of the yeast mitochondrial cyclophilin Cpr3 exhibit a low prolyl isomerase activity in both peptide and protein‐folding assays

FEBS Letters

Schmid, Franz X²  Heitman, Joseph¹  Scholz, Christian²  Dolinski, Kara¹  Maier, Peter² 

[1] Departments of Genetics and Pharmacology, Howard Hughes Medical Institute, Duke University Medical Center, Durham, NC 27710, USA;Biochemisches Laboratorium, Universität Bayreuth, D-95440 Bayreuth, Germany

关键词: Cyclophilin;    Immunophilin;    Prolyl isomerization;    Protein folding;    Mitochondrion;    CsA;    cyclosporin A;    RNase T1;    ribonuclease T1;    RCM-(S54G/P55N)-RNase T1;    disulfide-reduced and S-carboxymethylated form of a variant of RNase T1 with Ser54 and Pro55 replaced by Gly and Asn;    respectively;    Cpr3;    mitochondrial cyclophilin of Saccharomyces cerevisiae;   

DOI  :  10.1016/S0014-5793(98)01735-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Previously we reported that the R73A and H144Q variants of the yeast cyclophilin Cpr3 were virtually inactive in a protease-coupled peptide assay, but retained activity as catalysts of a proline-limited protein folding reaction [Scholz, C. et al. (1997) FEBS Lett. 414, 69–73]. A reinvestigation revealed that in fact these two mutations strongly decrease the prolyl isomerase activity of Cpr3 in both the peptide and the protein-folding assay. The high folding activities found previously originated from a contamination of the recombinant Cpr3 proteins with the Escherichia coli protein SlyD, a prolyl isomerase that co-purifies with His-tagged proteins. SlyD is inactive in the peptide assay, but highly active in the protein-folding assay.

【 授权许可】

Unknown