The folding of spectrin domains I: wild-type domains have the same stability but very different kinetic properties.
The study of proteins with the same architecture, but different sequence has proven to be a valuable tool in the protein folding field. As a prelude to studies on the folding mechanism of spectrin domains we present the kinetic characterisation of the wild-type forms of the 15th, 16th, and 17th domains of chicken brain alpha-spectrin (referred to as R15, R16 and R17, respectively). We show that the proteins all behave in a two-state manner, with different kinetic properties. The folding rate varies remarkably between different members, with a 5000-fold variation in folding rate and 3000-fold variation in unfolding rate seen for proteins differing only 1 kcal mol(-1) in stability. We show clear evidence for significant complexity in the energy landscape of R16, which shows a change in amplitude outside the stopped-flow timescale and curvature in the unfolding arm of the chevron plot. The accompanying paper describes the characterisation of the folding pathway of this domain.
Scott
Kathryn A
KA
MRC Centre for Protein Engineering, University of Cambridge Chemical Laboratory, Lensfield Road, Cambridge CB2 1EW, UK.
Batey
Sarah
S
Hooton
Karen A
KA
Clarke
Jane
J
D000818:Animals; D001923:Brain Chemistry; D002645:Chickens; D004355:Drug Stability; D007700:Kinetics; D008958:Models, Molecular; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics; D013049:Spectrin / Q000737:chemistry* / Q000235:genetics; D013816:Thermodynamics
D011994:Recombinant Proteins; D013049:Spectrin