Copper/zinc Sods of Salmonella Typhimurium: Enzymatic Properties and Correlation to Pathogenesis

Krishnakumar, Radha

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Description

Title

Copper/zinc Sods of Salmonella Typhimurium: Enzymatic Properties and Correlation to Pathogenesis

Author(s)

Krishnakumar, Radha

Issue Date

2006

Doctoral Committee Chair(s)

Slauch, James M.

Department of Study

Microbiology

Discipline

Microbiology

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

Biology, Microbiology

Language

eng

Abstract

"We have however, noted three significant differences between SodCI and SodCII: dimerization, tethering, and protease resistance. SodCI is a dimer and is not released from the periplasm by osmotic shock. Thus SodCI is ""tethered"" in the periplasm by some non-covalent interaction. In contrast, SodCII is monomeric and is quantitatively released by osmotic shock. Using site-directed mutagenesis we constructed a monomeric, fully active SodCI that is now released by osmotic shock. Thus dimerization is critical for tethering. Upon recombination of the monomeric SodCI allele into the normal chromosomal sodCI locus, we found that the resulting strain is avirulent when competed against the wild type strain, indicating that dimerization and/or tethering is crucial to virulence. Apparently, disrupting the dimeric conformation of SodCI also exposes some regions of the protein that renders SodCI sensitive to proteinase K digestion. This is in sharp contrast to wild-type SodCI, which is resistant to proteinase K. Thus it appears that SodCI must maintain its dimeric conformation, perhaps not for catalytic activity, but possibly to remain tethered within the periplasm in order to resist attack by host proteases, and also to retain its wild-type protease resistance."

Graduation Semester

2006

Type of Resource

text

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