Dr. Andrew Bigley

EDUCATION

Enzymology of Recently Evolved Bacterial Systems

Dr. Andrew N. Bigley (Mentor)

Accepting students Spring 2020 and future semesters.

Introduction. Xenobiotics are compounds which are purely manmade with no natural source. This class of compounds affords us a unique opportunity to examine the evolution of enzymatic activity as the date of environmental introduction is known. Prior to the last decade, evolution was thought to be a slow process working on geological time scales. Over the last ten years it has become increasingly apparent that bacteria are able to adapt to new chemicals in the environment in an amazingly short amount of time. Within approximately 30 years from their introduction bacterial systems were able to evolve metabolic pathways to utilized the herbicide atrazine and the organophosphate insecticide parathion. Despite the short time, the enzyme which hydrolyzes parathion has activity approaching the theoretical limits of efficiency. This impressive display of evolution has now been repeated in multiple bacterial systems against multiple xenobiotic compounds.
A class of xenobiotic compounds of rising concern is the organophosphorus flame retardants. These compounds are used in nearly all durable plastic and foam products. While important for controlling the flammability of the products they appear in, the compounds themselves are suspected carcinogens, developmental toxins and endocrine disruptors. Unfortunately, the high usage rates of these compounds (100s of tons per year) has led to environmental contamination. Despite their recent introduction a bacterial strain (Sphingobium sp. TCM1) (referred to as TCM1) has been identified which is able to utilize the organophosphate flame retardants as a nutrient source. Studying the enzymology of flame-retardant catabolism offers us the opportunity to develop the technology to safely remove these compounds from the environment, while at the same time gives us a chance to study the mechanism by which bacteria evolve new catalytic activities.

Research Plan. The second step in the degradation of the organophosphorus flame-retardants by TCM1 is catalyzed by the enzyme Sb-PDE. This enzyme is a member of the polymerase and histidinol phosphatase (PHP) family of enzymes. The PHP family of enzymes normally catalyzes the hydrolysis of phosphate monoesters, and Sb-PTE is only the second known example of a PHP member which can catalyze a diesterase reaction. Bioinformatic analysis has provided evidence that Sb-PDE is a member of a small subgroup of the PHP family of enzymes with 12 members. There is currently no information on the sequence of structural basis for the ability of Sb-PDE to hydrolyze diesters. To address this and develop an understanding of how these members of the PHP family have evolved this new ability the gene for Sb-PDE and close homologs will be cloned into commercial expression vectors for heterologous expression in E. coli. The enzymes will be expressed and characterized against a set of select substrates and crystal trials will be conducted to identify conditions under which the structure of Sb-PDE can be determined. Students working on this project will receive training in cloning and expression, enzyme kinetics, and structural biology.

CONTACT INFORMATION

Email: andrew.bigley@swosu.edu Office Number: CPP 202-E
Phone Number: 580-774-3054

TEACHING: BASIC COURSES

CHEM 1004 Gen Chem
CHEM 1004L Gen Chem Lab
CHEM 1203 Gen Chem I
CHEM 1252 Gen Chem I Lab
CHEM 1303 Gen Chem II
CHEM 1352 Gen Chem II Lab

TEACHING: BIOCHEMISTRY

CHEM 4124 Biochemistry
CHEM 4124L Biochemistry Lab
CHEM 4011 Biochemistry Lab
CHEM 4673 Advanced Metabolism (no lab)

OTHER ACTIVITIES

AUG 2021-PRESENT
Chemistry Club Sponsor

RECENT PUBLICATIONS

Bigley AN, Harvey SP, Narindoshvili T, & Raushel FM. (2021 Sep 8). Substrate analogs for the enzyme-catalyzed detoxification of the organophosphate nerve agents Sarin, Soman, and Cyclosarin. Biochemistry.
PMID: 34494832
doi: 10.1021/acs.biochem.1c00361

Bigley AN, Narindoshvili T, & Raushel FM. (2020 Aug 25). A chemoenzymatic synthesis of the (Rp)-isomer of the antiviral prodrug Remdesivir. Biochemistry, 59(33), 3038-3043.
PMID: 32786401
doi: 10.1021/acs.biochem.0c00591

Bigley AN, Narindoshvili T, Xiang DF, & and Raushel FM. (2020 Mar 31). Stereoselective formation of multiple reaction products by the phosphotriesterase from Sphingobium sp. TCM1. Biochemistry, 59(12), 1273-1288.
PMID: 32167750
doi: 10.1021/acs.biochem.0c00089

Xiang DF, Bigley AN, Desormeaux E, Narindoshvili T, & Raushel FM. (2019 Jul 23). Enzyme-catalyzed kinetic resolution of chiral precursors to antiviral prodrugs. Biochemistry, 58(29), 3204-3211.
PMID: 31268686
doi: 10.1021/acs.biochem.9b00530

Bigley AN, Desormeaux E, Xiang DF, Bae SY, Harvey SP, Raushel FM. (2019 Apr 16). Overcoming the challenges of enzyme evolution to adapt phosphotriesterase for V-agent decontamination. Biochemistry, 58(15), 2039-2053.
PMID: 30893549
doi: 10.1021/acs.biochem.9b00097

Bigley AN, Xiang DF, Narindoshvili T, Burgert CW, Hengge AC, Raushel FM. (2019, Mar 5). Transition state analysis of the reaction catalyzed by the phosphotriesterase from Sphingobium sp. TCM1. Biochemistry, 58(9), 1246-1259.
PMID: 30730705
doi: 10.1021/acs.biochem.9b00041