Characterization of the Folding of a 5₂-Knotted Protein Using Engineered Single-Tryptophan Variants.

ABSTRACT: An increasing number of proteins that contain topological knots have been identified over the past two decades; however, their folding mechanisms are still not well understood. UCH-L1 has a 5₂-knotted topology. Here, we constructed a series of variants that contain a single tryptophan at different locations along the polypeptide chain. A study of the thermodynamic properties of the variants shows that the structure of UCH-L1 is remarkably tolerant to incorporation of bulky tryptophan side chains. Comprehensive kinetic studies of the variants reveal that they fold via parallel pathways on which there are two intermediate states very similar to wild-type UCH-L1. The structures of the intermediate states do not change significantly with mutation and therefore occupy local minima on

SUBMITTER: Zhang H 

PROVIDER: S-EPMC5192476 | biostudies-literature | 2016 Dec

REPOSITORIES: biostudies-literature