ja210118w_si_001.pdf (72.11 kB)
Domain Swapping Proceeds via Complete Unfolding: A 19F- and 1H-NMR Study of the Cyanovirin-N Protein
journal contribution
posted on 2016-02-21, 18:39 authored by Lin Liu, In-Ja L. Byeon, Ivet Bahar, Angela M. GronenbornDomain swapping creates protein oligomers by exchange
of structural
units between identical monomers. At present, no unifying molecular
mechanism of domain swapping has emerged. Here we used the protein
Cyanovirin-N (CV–N) and 19F-NMR to investigate the
process of domain swapping. CV–N is an HIV inactivating protein
that can exist as a monomer or a domain-swapped dimer. We measured
thermodynamic and kinetic parameters of the conversion process and
determined the size of the energy barrier between the two species.
The barrier is very large and of similar magnitude to that for equilibrium
unfolding of the protein. Therefore, for CV–N, overall unfolding
of the polypeptide is required for domain swapping.