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Article

  • The EMBO Journal (2008) 27, 1525 - 1535
  • doi:10.1038/emboj.2008.82

Published online: 1 May 2008

Biological function in a non-native partially folded state of a protein

Francesco Bemporad1, Joerg Gsponer2, Harri I Hopearuoho2, Georgia Plakoutsi1, Gianmarco Stati1, Massimo Stefani1, Niccolò Taddei1, Michele Vendruscolo2 and Fabrizio Chiti1

  1. Dipartimento di Scienze Biochimiche, Università degli Studi di Firenze, Firenze, Italy
  2. Department of Chemistry, University of Cambridge, Cambridge, UK

Correspondence to:

Fabrizio Chiti, Dipartimento di Scienze Biochimiche, Università di Firenze, viale Morgagni 50, Firenze I-50134, Italy. Tel.: +39 055 459 8319; Fax: +39 055 459 8905; E-mail: fabrizio.chiti@unifi.it

Received 7 February 2008; Accepted 31 March 2008

As structural flexibility is known to be required for enzyme catalysis and pattern recognition and a significant fraction of eukaryotic proteins appear to be unfolded or contain unstructured regions, biological activity of conformational states distinct from fully folded structures could be more common than previously thought. By applying a procedure that allows the recovery of enzymatic activity to be monitored in real time, we show that a non-native state populated transiently during folding of the acylphosphatase from Sulfolobus solfataricus is enzymatically active. The structural characterization of this partially folded state reveals that enzymatic activity is possible even if the catalytic site is structurally heterogeneous, whereas the remainder of the structure acts as a scaffold. These results extend the spectrum of biological functions carried out in the absence of a folded state to include enzyme catalysis.

  • Keywords:

    • enzyme dynamics,
    • folding nucleus,
    • intrinsically disordered proteins,
    • Phi-value,
    • protein evolution