2026-09-20T01:21:21.392285100Zhttps://opus.uleth.ca/server/oai/requestoai:opus.uleth.ca:10133/24732019-02-07T06:05:12Zcom_10133_3346com_10133_1com_10133_296col_10133_3347col_10133_298
ULethbridge OPUS Repository
supervisor
Mosimann, Steven C.
supervisor
Selinger, L. Brent
author
Gruninger, Robert J.
author
University of Lethbridge. Faculty of Arts and Science
2011-07-08T19:43:16Z
2011-07-08T19:43:16Z
2009
https://hdl.handle.net/10133/2473
The structure and mechanism of the Protein Tyrosine Phosphatase-like Phytases (PTPLPs) from Selenomonas ruminantium (PhyAsr) and Mitsuokella multacida (PhyAmm) were investigated using a combination of enzyme kinetics, site-directed mutagenesis, and X-ray crystallography. I show that PTPLPs use a classical protein tyrosine phosphatase catalytic mechanism and adopt a core PTP fold. Several unique structural features of PTPLPs confer specificity for inositol phosphates. The effect of ionic strength and oxidation on the kinetics and structure of PTPLPs was investigated. The structural consequences of reversible and irreversible oxidation on PTPLPs and PTPs are compared and discussed. We determine the structural basis of substrate specificity in PTPLPs and propose a novel reaction mechanism for the hydrolysis of inositol polyphosphates by PTPLPs. Finally, the structure and function of a unique tandemly repeated phytase has been determined. We show that the active sites of the tandem repeat possess significantly different specificities for inositol polyphosphate.
en_US
Phytases
Protein-tyrosine kinase
Phosphorylation
Dissertations, Academic
Structure and mechanism of protein tyrosine phosphatase-like phytases
Thesis
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URL
http://localhost:4000/bitstreams/321a822a-0916-442f-b91c-47ffa7596065/download
File
MD5
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application/pdf
GRUNINGER_ROBERT_PHD_2009.pdf
URL
http://localhost:4000/bitstreams/1818f015-4020-4eb6-b565-18ee6825aefd/download
File
MD5
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text/plain
GRUNINGER_ROBERT_PHD_2009.pdf.txt