Mechanism of assembly of the non-covalent spectrin tetramerization domain from intrinsically disordered partners.
Interdomain interactions of spectrin are critical for maintenance of the erythrocyte cytoskeleton. In particular, "head-to-head" dimerization occurs when the intrinsically disordered C-terminal tail of β-spectrin binds the N-terminal tail of α-spectrin, folding to form the "spectrin tetramer domain". This non-covalent three-helix bundle domain is homologous in structure and sequence to previously studied spectrin domains. We find that this tetramer domain is surprisingly kinetically stable. Using a protein engineering Φ-value analysis to probe the mechanism of formation of this tetramer domain, we infer that the domain folds by the docking of the intrinsically disordered β-spectrin tail onto the more structured α-spectrin tail.
University of Cambridge Chemical Laboratory, Lensfield Road, Cambridge CB2 1EW, UK; Laboratory of Molecular Biophysics, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
Stephanie A
SA
Hill
University of Cambridge Chemical Laboratory, Lensfield Road, Cambridge CB2 1EW, UK.
Lee Gyan
LG
Kwa
University of Cambridge Chemical Laboratory, Lensfield Road, Cambridge CB2 1EW, UK.
Sarah L
SL
Shammas
Laboratory of Molecular Biophysics, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
Jennifer C
JC
Lee
University of Cambridge Chemical Laboratory, Lensfield Road, Cambridge CB2 1EW, UK. Electronic address: jc162@cam.ac.uk.
Jane
J
Clarke
D007700:Kinetics; D017510:Protein Folding; D054730:Protein Interaction Domains and Motifs; D055503:Protein Multimerization; D055550:Protein Stability; D013049:Spectrin / Q000737:chemistry* / Q000378:metabolism*
D013049:Spectrin
GdmCl; IDP; ITC; NIH; National Institutes of Health; guanidinium chloride; intrinsically disordered protein; isothermal titration calorimetry; natively unfolded protein; protein engineering; protein folding; Φ-value analysis