The Function of Inosine-5’-Monophosphate Dehydrogenase’s Bateman Domain in Escherichia coli

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dc.contributor.advisor Hedstrom, Lizbeth McDonnell, Sabrina 2018-05-15T17:18:45Z 2018-05-15T17:18:45Z 2018
dc.description.abstract Inosine 5’-monophosphate dehydrogenase (IMPDH) catalyzes the rate-limiting conversion of inosine 5’-monophosphate (IMP) to xanthosine 5’-monophosphate (XMP) in the de novo purine biosynthesis pathway. Overexpression of the protein is linked to the proliferation of diseased cells, and inhibitors of IMPDH have been used as anticancer, antiviral, and immunosuppressive treatments. IMPDH is a tetramer and each monomer has two domains: a catalytic domain and a Bateman domain. The function of the Bateman domain is currently unknown. The enzyme remains catalytically active when the Bateman domain is replaced with a short peptide scar (ΔCBS). Mutations in the Bateman domain of human IMPDH 1 have been linked to hereditary diseases including retinitis pigmentosa. Understanding the function of the Bateman domain in E. coli will shed light on IMPDH’s extracatalytic functions. I constructed E. coli strains that can endogenously express Strep-II tagged IMPDH and IMPDHΔCBS and used affinity purification to test for the presence of binding partners. E. coli cells were harvested during exponential growth and incubated with formaldehyde to chemically cross-link protein-protein and protein-nucleotide interactions prior to lysis. Western blots of IMPDH and IMPDHΔCBS from cross-linked lysates revealed cross-link dependent band shifts that corresponded with the molecular weight of their respective dimer, trimer, and tetramer. There was also a cross-link dependent shift of the wild-type IMPDH monomer that was absent in the IMPDHΔCBS sample, which indicates that the shift was dependent on an interaction with the Bateman domain. Mass spectrometry was inconclusive for determining a protein-binding partner for the Bateman domain, but both the WT tagged and ΔCBS tagged samples contained GMP reductase (GMPR) and adenosine deaminase. Additional research is required to identify the function of these interactions and the molecule(s) that interact with the Bateman domain.
dc.description.sponsorship Brandeis University, Graduate School of Arts and Sciences
dc.format.mimetype application/pdf
dc.language English
dc.language.iso eng
dc.publisher Brandeis University
dc.relation.ispartofseries Brandeis University Theses and Dissertations
dc.rights Copyright by Sabrina McDonnell 2018
dc.title The Function of Inosine-5’-Monophosphate Dehydrogenase’s Bateman Domain in Escherichia coli
dc.type Thesis
dc.contributor.department Department of Biochemistry MS Masters Biochemistry Brandeis University, Graduate School of Arts and Sciences

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