Description:

Kristala L. J. Prather
Arthur D. Little Professor of Chemical Engineering
Massachusetts Institute of Technology

Enzyme Design and Screening for Metabolic Pathway Engineering

Biological synthesis is increasingly being pursued as an alternative to traditional organic synthesis for the production of chemical compounds. As known biochemical pathways are transferred to non-native hosts and new pathways are designed, access to genes encoding desired enzymatic activities with appropriately high reaction rates is often a limiting factor. In this presentation, I will discuss our efforts to identify enzymes with appropriate activity and selectivity in the context of two novel biosynthetic pathways. In the first example, we have exploited the promiscuous activity of four different enzymes in order to build a versatile platform pathway for the synthesis of various 3-hydroxyalkanoic acids. However, significant activity towards native substrates results in significant levels of undesired byproducts. Working with collaborators, we have generated enzyme variants that display significantly altered specificity towards the desired products. Realizing these results also required the development of new screening methods. Using a second model pathway for the production of glucaric acid, I will describe opportunities to use experimental data to guide the selection of additional enzyme variants that may have higher target activities through a bioprospecting approach that involves network analysis of protein sequences.

Kristala Jones Prather is the Arthur D. Little Professor of Chemical Engineering at MIT. She received an S.B. degree from MIT in 1994 and Ph.D. from the University of California, Berkeley (1999), and worked 4 years in BioProcess Research and Development at the Merck Research Labs prior to joining the faculty of MIT. Her research interests are centered on the design and assembly of recombinant microorganisms for the production of small molecules, with additional efforts in novel bioprocess design approaches. A particular focus is the elucidation of design principles for the production of unnatural organic compounds with engineered control of metabolic flux within the framework of the burgeoning field of synthetic biology. Prather is the recipient of an Office of Naval Research Young Investigator Award (2005), a Technology Review “TR35” Young Innovator Award (2007), a National Science Foundation CAREER Award (2010), the Biochemical Engineering Journal Young Investigator Award (2011), and the Charles Thom Award of the Society for Industrial Microbiology and Biotechnology (2017). Additional honors include selection as the Van Ness Lecturer at Rensselaer Polytechnic Institute (2012), and as a Fellow of the Radcliffe Institute for Advanced Study (2014-2015). Prather has been recognized for excellence in teaching with the C. Michael Mohr Outstanding Faculty Award for Undergraduate Teaching in the Dept. of Chemical Engineering (2006, 2016), the MIT School of Engineering Junior Bose Award for Excellence in Teaching (2010), and through appointment as a MacVicar Faculty Fellow (2014), the highest honor given for undergraduate teaching at MIT.