Early Events in the Folding of the Protein Ubiquitin

The equilibrium and non-equilibrium behavior of several mutants of the small single-domain protein ubiquitin have been characterized, with an eye towards describing the early folding events. These events have been interrogated by a fast laser temperature-jump technique and by low temperature stopped flow mixing. In the case of the T-Jump, initially cold denatured protein solution is rapidly heated with a 20 nsec heating pulse. The subsequent refolding is monitored by time resolved fluorescence lifetime and spectrum. In the case of stopped flow mixing, an initially chemically denatured protein sample is diluted into a refolding buffer at temperatures as low as -20°. Here X-ray scattering, circular dichroism, and fluorescence intensity are followed as a function of time. The two techniques reveal two unexpected results. Non-exponential kinetics have been recorded in protein refolding studies for the first time, and a transient structure containing more alpha-helix than the native state has been observed during the protein's folding.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Chemistry

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Ervin, John Lawrence

Contributors dc:contributor

• Martin Gruebele

• Chemistry, Biochemistry

Language dc:language

eng

Identifier

(MiAaPQ)AAI3030429

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/84056