Two immunoglobulin tandem proteins with a linking β-strand reveal unexpected differences in cooperativity and folding pathways.

ABSTRACT: The study of the folding of single domains, in the context of their multidomain environment, is important because more than 70% of eukaryotic proteins are composed of multiple domains. The structures of the tandem immunoglobulin (Ig) domain pairs A164-A165 and A168-A169, from the A-band of the giant muscle protein titin, reveal that they form tightly associated domain arrangements, connected by a continuous β-strand. We investigate the thermodynamic and kinetic properties of these tandem domain pairs. While A164-A165 apparently behaves as a single cooperative unit at equilibrium, unfolding without the accumulation of a large population of intermediates, domains in A168-A169 behave independently. Although A169 appears to be stabilized in the tandem protein, we show that this is due to nonsp

SUBMITTER: Steward A 

PROVIDER: S-EPMC3277889 | biostudies-literature | 2012 Feb

REPOSITORIES: biostudies-literature