Elizabeth Gillam

Biography

After graduating from UQ with first class Honours in Biochemistry, Elizabeth took up a Royal Commission for the Exhibition of 1851 Overseas Scholarship to pursue doctoral work at Oxford University then undertook postdoctoral work at the Center in Molecular Toxicology and Department of Biochemistry at Vanderbilt University School of Medicine with Prof. F.P. Guengerich. She returned to UQ in 1993 to take up a position in Pharmacology and joined the School of Chemistry and Molecular Biosciences in 2009 as a Professor of Biochemistry.

Research Interest

Research in the Gillam lab focuses on cytochrome P450 enzymes, especially those responsible for xenobiotic metabolism in humans. These are enzymes of exceptional versatility, able to catalyse over 60 different chemical reactions and being responsible for the clearance of a practically unlimited variety of chemicals from the body. Structural and functional studies on P450s should yield fundamental insights into how enzyme structure determines function. Moreover, the biotechnological potential of P450s remains to be exploited. Directed (or artificial) evolution: a way of exploring the sequence space and catalytic potential of P450s The demonstrated catalytic diversity of P450 enzymes makes them the ideal starting material for engineering sophisticated chemical reagents to catalyse difficult chemical transformations. We are using recombinatorial directed evolution to generate libraries of mutants from naturally-occurring P450 forms with the aim of selecting for properties that are commercially useful. This technique has been proven to be able to "breed" enzyme catalysts with properties enhanced by orders of magnitude over those found in naturally occurring enzymes. We are currently evolving enzymes for use in drug discovery and development in collaboration with Dr. Martin Hayes at AstraZeneca, Sweden, and for use in bioremediation with Dr. John Oakeshott from the CSIRO, Canberra. Factors controlling enzyme catalysis and catalytic promiscuity in P450 enzymes Collectively P450s of the 3A, 2D and 2C subfamilies handle about 95% of all drugs and other chemicals to which humans are exposed. This substrate range is truly exceptional. We are studying these enzymes to determine how they can metabolise so many substrates – i.e. show catalytic promiscuity - while retaining some degree of regio- and chemoselectivity towards certain substrates. In particular, comparisons of catalytically promiscuous, native forms with evolved enzymes specialised towards one particular substrate, should allow us to understand the structural basis to catalytic promiscuity in these highly versatile enzymes. Recently we have discovered that P450s are present within cells in the Fe(II) form, a finding that has led to a radical revision of the dogma concerning the P450 catalytic cycle, and has implications for the control of uncoupling of P450 activity in cells. Enzyme design. In collaboration with Dr. Mikael Boden we are developing novel bioinformatic methods by which to predict functional properties of enzymes based on analysis of enzyme libraries. The aim of this work is to provide accurate models of enzyme properties which can be used to design biocatalysts with desired properties. Secondary Research Areas: Biomolecular Chemistry Medicinal Chemistry Molecular Genetics and Genomics Science Education