The overall goal of this project is to expand asymmetric synthesis techniques through biocatalysis. It includes three specific aims. Specific aim 1 involves the screening of a variety of prochiral substrates (ketones and oximes) against a library of engineered E. coli yeast reductases that have been characterized as excellent asymmetric reducing agents. Specific aim 2 involves the molecular modeling studies of 2,5-Diketo-D-gluconic acid reductase. In this reductase, the enzyme substrate interaction and its correlation with Si or Re face hydride transfer will be investigated. In specific aim 3, representative yeast reductases will be systematically mutated and the effects on the asymmetric reduction on known substrates will be determined. The goal of this aim is to attain a more accurate understanding of the enzyme-substrate complex and its role in determining enzyme stereoselectivity with the intention of improving asymmetric catalysts.
With this award, the Organic and Macromolecular Chemistry Program is supporting the research of Professor Brent Feske (Department of Chemistry and Physics), Professor Clifford Padgett (Department of Chemistry and Physics), and Professor Scott Mateer (Department of Biology) at Armstrong Atlantic State University. The combined research of these professors will investigate the use of enzymes to synthesize complex molecules with asymmetric centers. Successful development of this methodology will afford greener and more efficient routes to these molecules, which are needed in large numbers in the pharmaceutical industry.
Intellectual Merit This award funded research in the area of biocatalysis, which is the use of enzymes or whole cells to catalyze chemical reactions. Biocatalysis is advantageous because it is considered a "green chemical" process because it uses 'natures' catalyst' in water to conduct the reaction. In addition, many pharmaceuticals demand a higher purity (pure stereoisomers) and enzymes are an effective way to produce this purity. As a result, we have studied a specific class of enzymes for their ability to produce pharmaceuticals and pharmaceutical intermediates. Specifically, we have developed routes to the antibiotic Fosfomycin, serotonin reuptake inhibitors such as Prozac, and also a variety of β-blockers. We also developed a synthesis to a class of compounds called lactones. These are most popular for their use as perfumes and also pheromones (chemical messengers used by insects to communicate). In addition to these synthetic accomplishments we have also studied how these enzymes work by building computational models that predict how these enzymes bind the substrate. Furthermore, we have manipulated parts of this enzyme to better understand what specific amino acids play an important role in substrate binding. This has directly led to 4 peer reviewed publications (all with undergraduate student coauthors) with 2 more publications to follow. In addition, there have been over 20 presentations at National, Regional, and local conferences that have resulted from this award. Broader Impacts All of the above mentioned work was carried out in the hands of undergraduate students. The PI’s believe that it is of equal importance that these students get the hands on experience and thus the experiential learning associated with this research. This research project has incorporated over 25 undergraduate student collaborators many of which are underrepresented minorities and groups. To promote the optimal learning experience this interdisciplinary biocatalysis group held biweekly group meetings which involve undergraduate students presenting and then discussing their past, present, and future research. Rotating with this schedule, the biocatalysis group also meets every two weeks for journal club, which a new paper in our research area will be chosen to be read and discussed by the group. This research group has also actively participated in an NSF-STEP grant, which brings in young aspiring scientists (usually 17 or 18 years old) to conduct research in the lab the summer before their freshman year. If they meet all of the criteria they are then able to work the next summer as well. This is an excellent way to get young science majors excited about their chosen major with the goals of increasing retention in STEM. In addition, we also brought this interdisciplinary research into an upper level biology class. Biology majors who took this course were exposed to many facets of this project and ultimately this novel interdisciplinary teaching approach was published in a peer reviewed journal.
