A Search for the Cause of Excess Thiol Sensitivity in a Mutant of ESCHERICHIA COLI

Author

Hongying Zeng

Abstract

The subject of this study was a search for the biochemical basis of hypersensitivity to thiols in a mutant of Escherichia coli (IS16). A 1.3 kb chromosomal fragment from E. coli (introduced into the mutant on a plasmid) successfully abolished the hypersensitivity. This fragment contained only one intact gene, ubiX, which codes for polyprenyl-4-hydroxybenzoatelyase. The decarboxylation of octaprenyl-4- hydroxybenzoate in E. coli is catalyzed not only by the ubiX protein but also by the product of ubiD. The ubiquinone content of IS16 was only 2% of that of its parent strain, while the complementing plasmid increased it to 200%. The ubiX genes were amplified from the parent (THU) and from the thiol sensitive mutant (IS16) by PCR and they were sequenced. They had identical sequences which were considerably different from the published sequence. It is therefore assumed that the parent strain was a ubiX genotype, while the thiol sensitive mutant was a ubiXubiD genotype. Thiol hypersensitivity is postulated to be the consequence of the extremely low ubiquinone content.

LLU Discipline

Biochemistry

Department

Biochemistry

School

Graduate School

First Advisor

George T. Javor

Second Advisor

E. Clifford Herrmann

Third Advisor

Charles W. Slattery

Degree Name

Master of Science (MS)

Degree Level

M.S.

Year Degree Awarded

1997

Date (Title Page)

3-1997

Language

English

Library of Congress/MESH Subject Headings

Sulfhydryl Compounds -- pharmacology; Drug Hypersensitivity; Escherichia coli -- physiology.

Type

Thesis

Page Count

vii; 40

Digital Format

PDF

Digital Publisher

Loma Linda University Libraries

Copyright

Author

Usage Rights

This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.

Recommended Citation

Zeng, Hongying, "A Search for the Cause of Excess Thiol Sensitivity in a Mutant of ESCHERICHIA COLI" (1997). Loma Linda University Electronic Theses, Dissertations & Projects. 1902.
https://scholarsrepository.llu.edu/etd/1902

Collection

Loma Linda University Electronic Theses and Dissertations

Collection Website

http://scholarsrepository.llu.edu/etd/

Repository

Loma Linda University. Del E. Webb Memorial Library. University Archives