Graduation Year


Document Type

Campus Only Senior Thesis

Degree Name

Bachelor of Arts



Reader 1

Steven G. Clarke

Reader 2

Emily Wiley

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Protein arginine methyltransferases (PRMTs) are a group of nine sequence-related mammalian enzymes that catalyze the formation of monomethylarginine (MMA), asymmetric dimethylarginine (ADMA), and symmetric dimethylarginine (SDMA) residues with the cofactor S-adenosylmethionine. PRMT7, which forms only MMA residues, is known to be involved in processes including muscle formation, stem cell regulation, and transcriptional regulation. Overexpression of PRMT7 is found in breast cancers. Relatively little is known about the structure and enzymology of human PRMT7, although it is believed to crystallize with a bound zinc ion based on sequence similarities and the crystal structures of mouse and nematode PRMT7. Past studies have revealed that PRMT7 is inhibited by physiologically normal salt concentrations. In order to explore the metal ion dependence and salt inhibition of PRMT7, the activity of the enzyme in a variety of salts, including metal ions, was analyzed using peptide sequences derived from residues 23-37 of human histone H2B and residues 1-21 of human histone H4 as methyl-accepting substrates. All tested salts inhibited the activity, with the largest effects seen with magnesium(II) chloride and surprisingly zinc(II) chloride. Inhibition was also observed with the metal chelator EDTA but not with the related compound EGTA. In addition, PRMT7 was inactived at pH 6.5

This thesis is restricted to the Claremont Colleges current faculty, students, and staff.