2018-2019 Grant in Aid of Research

A Study of Inactive Enzyme-Homologues: The Biochemical and Biological Function of Ecm14 in Saccharomyces cerevisiae

Robert C. McDonald

Many enzyme families contain both catalytically active and inactive members. Although these inactive enzyme-homologues share significant similarity with their active counterparts, key modifications seem to suggest a loss of traditional catalytic activity. The obscure function of these pseudoenzymes makes them inherently difficult to study. Therefore, a quantifiable phenotype is fundamentally needed in order to systematically study the biochemical and biological functions of these pseudoenzymes. Although previous studies have suggested that pseudoenzymes are involved in the non-catalytic binding of other proteins, much work remains in order to clarify and demonstrate the function of these inactive-enzyme homologous in general. In the proposed research, I will investigate the biochemical and biological function of Ecm14, an inactive member of the M14 metallocarboxypeptidase family found in baker’s yeast, S. cerevisiae. I will do this by performing a genome-wide screen for genes that confer synthetic lethality (a quantifiable phenotype) with ECM14 deletion. Whole genome sequencing will subsequently be performed in order to identify these putatively synthetically lethal gene pairs. The identification of synthetically lethal ECM14 gene pairs serves as a critical ‘next step’ in elucidating the function of the key modifications of Ecm14 in S. cerevisiae. Thus, using this technical approach can serve as a potential model for future investigations of inactive enzyme-homologues in general.