Early Events in the Folding of the Protein Ubiquitin

Ervin, John Lawrence

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Description

Title

Early Events in the Folding of the Protein Ubiquitin

Author(s)

Ervin, John Lawrence

Issue Date

2001

Doctoral Committee Chair(s)

Martin Gruebele

Department of Study

Chemistry

Discipline

Chemistry

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

Chemistry, Biochemistry

Language

eng

Abstract

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.

Graduation Semester

2001

Type of Resource

text

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http://hdl.handle.net/2142/84056

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