Essential role of Pro 74 in stefin B amyloid-fibril formation: Dual action of cyclophilin A on the process

Smajlović, Aida; Berbić, Selma; Schiene-Fischer, Cordelia; Tušek-Žnidarič, Magda; Taler, Ajda; Jenko-Kokalj, Saša; Turk, Dušan; Žerovnik, Eva

doi:10.1016/j.febslet.2009.02.037

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Volume 583, Issue 7 , Pages 1114-1120, 2 April 2009

Essential role of Pro 74 in stefin B amyloid-fibril formation: Dual action of cyclophilin A on the process

Edited by Jesus Avila

Aida Smajlović
- Department of Biochemistry, Farmaceutical Faculty, University of Tuzla, Univerzitetska 8, 75000 Tuzla, Bosnia and Herzegovina
- The two authors contributed equally.
Selma Berbić
- Department of Biochemistry, Farmaceutical Faculty, University of Tuzla, Univerzitetska 8, 75000 Tuzla, Bosnia and Herzegovina
Cordelia Schiene-Fischer
- Max Planck Research Unit for Enzymology of Protein Folding, Weinbergweg 22, 06120 Halle/Saale, Germany
Magda Tušek-Žnidarič
- Department of Plant Physiology and Biotechnology, National Institute of Biology, Večna pot 111, 1000 Ljubljana, Slovenia
Ajda Taler
- Department of Biochemistry, Molecular and Structural Biology, Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
- The two authors contributed equally.
Saša Jenko-Kokalj
- Department of Biochemistry, Molecular and Structural Biology, Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
Dušan Turk
- Department of Biochemistry, Molecular and Structural Biology, Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
Eva Žerovnik
- Department of Biochemistry, Molecular and Structural Biology, Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
- Corresponding author. Fax: +386 1 477 3984.

Received 27 January 2009; received in revised form 16 February 2009; accepted 26 February 2009. published online 03 March 2009.

Abstract

We report that Pro74 in human stefin B is critical for fibril formation and that proline isomerization plays an important role. The stefin B P74S mutant did not fibrillate over the time of observation at 25°C, and it exhibited a prolonged lag phase at 30°C and 37°C. The peptidyl prolyl cis/trans isomerase cyclophilin A, when added to the wild-type protein, exerted two effects: it prolonged the lag phase and increased the yield and length of the fibrils. Addition of the inactive cyclophilin A R55A variant still resulted in a prolonged lag phase but did not mediate the increase of the final fibril yield. These results demonstrate that peptidyl prolyl cis/trans isomerism is rate-limiting in stefin B fibril formation.