Kevin D. Walker
Research
Constructing Enzyme Cascade Reactions toward Bioactive and Commodity Compounds
(Research Description PDF)
A More Complete Research Description (click here)
We use interdisciplinary methods to evaluate enzyme catalysts from various sources, such as bacteria, plants, and yeast, with non-natural substrates. Our vision is to transform natural compounds or synthetically-derived chemicals into novel products. Transfer of the genes encoding native or bioengineered enzymes into a chassis organism can potentially make various bioactive or commodity molecules in vivo or in vitro.
Area(s) of Interest
Organic (Or)
Biological (Bi)
Selected Publications
For Complete Listing of Publications and Patents (click here)
Assessing Alkyl Methoxypyrazines as Predictors of the Potato Taste Defect in Coffee, Shingiro, J.B.; Shee, P.K.; Beaudry, R.M.; Thiagarajan, D.; Bourquin, L.D.; Walker,
K.D. ACS Food Sci. Technol. 2022, accepted.
Biocatalysis of precursors to new-generation SB-T-taxanes effective against paclitaxel-resistant cancer cells, A. Al-Hilfi; K.D. Walker. Arch. Biochem. Biophys. 2022, 719, online. DOI: 10.1016/j.abb.2022.109165
A Semibiocatalytic Approach toward Regioisomerically Enriched Ethyl Dimethylpyrazines Important in Flavor Industries, G. Attanayake; G. Mao; K.D. Walker. J. Agric. Food Chem. 2021, 69 (50) 15314–15324. DOI: 10.1021/acs.jafc.1c05786.
PATENT: Developing a Semibiocatalytic Process toward Regioisomerically Enriched Alkyl Pyrazines, G. Attanayake; G. Mao; K.D. Walker. Filed, July 13, 2021.
Intermolecular amine transfer to enantioenriched trans-3-phenylglycidates by an α/β-aminomutase to access both anti-phenylserine isomers, P.K. Shee; H. Yan; K.D. Walker. ACS Catal. 2020, 10, 15071-15082. DOI: 10.1021/acscatal.0c03977
CoA Recycling by a Benzoate Coenzyme A Ligase in Cascade Reactions with Aroyltransferases to Biocatalyze Paclitaxel Analogs, S.A. Sullivan, ; I.N. Nawarathne; K.D. Walker. Arch. Biochem. Biophys. 2020, Arch. Biochem. Biophys. 2020, 683, 108276. DOI: 10.1016/j.abb.2020.108276
Exploring the Scope of an α/β-Aminomutase for the Amination of Cinnamate Epoxides to Arylserines and Arylisoserines, P.K. Shee; N.D. Ratnayake; T. Walter; O. Goethe; E.N. Onyeozili; K.D. Walker. ACS Catal. 2019, 9, 7418-7430. DOI: 10.1021/acscatal.9b01557
Understanding Which Residues of the Active Site and Loop Structure of a Tyrosine Aminomutase Define its Mutase and Lyase Activities, G. Attanayake; T. Walter; K. D. Walker. Biochemistry (ACS), 2018, 57 (25), 3503–3514. DOI: 10.1021/acs.biochem.8b00269 in Special Issue: Current Topics in Mechanistic Enzymology
Biocatalysis of a Paclitaxel Analogue: Conversion of Baccatin III to N-Debenzoyl-N-(2-furoyl)paclitaxel and Characterization of an Amino Phenylpropanoyl CoA Transferase. C.K. Thornburg; T. Walter; K.D. Walker. Biochemistry (ACS) 2017, 56 (44), 5920–5930. DOI: 10.1021/acs.biochem.7b00912.
Paclitaxel Biosynthesis: Adenylation and Thiolation Domains of an NRPS TycA PheAT Module Produce Various Arylisoserine CoA Thioesters. R. Muchiri; K.D. Walker. 2017, Biochemistry (ACS) 56 (10), 1415–1425: DOI: 10.1021/acs.biochem.6b01188.
| Identification and characterization of the missing phosphatase on the riboflavin biosynthesis pathway in Arabidopsis thaliana. N. Sa; R. Rawat; C.K. Thornburg; K.D. Walker; S. Roje. 2016, Plant J. 88 (5), 705–716 DOI: 10.1111/tpj.13291 Featured Article. |  |
Mutation of aryl binding-pocket residues results in an unexpected activity switch in an Oryza sativa tyrosine aminomutase. T. Walter; D. Wijewardena; K.D. Walker, Biochemistry, 2016, 55 (25), 3497–3503 DOI: 10.1021/acs.biochem.6b00331.
Layer-by-layer deposition with polymers containing nitrilotriacetate, a convenient route to fabricate metal- and protein-binding films. S. Wijeratne; W. Liu; J. Dong; W. Ning; N.D. Ratnayake; K.D. Walker; M.L. Bruening, ACS Appl. Mater. Interfaces, 2016, 8, 10164–10173 DOI: 10.1021/acsami.6b00896
A Tyrosine Aminomutase from Rice (Oryza sativa) Isomerizes (S)-α- to (R)-β-Tyrosine with Unique High Enantioselectivity and Retention of Configuration. T. Walter; Z. King; K. D. Walker, Biochemistry, 2016, 55 (1), 1–4 DOI: 10.1021/acs.biochem.5b01331
Whole-cell biocatalytic production of variously substituted β-aryl- and β-heteroaryl-β-amino acids, N. D. Ratnayake; C. Theisen.; T. Walter; K. D. Walker, J. Biotechnol., 2016, 217, 12–21. DOI: 10.1016/j.jbiotec.2015.10.012
Kinetically and crystallographically guided mutations of a benzoate CoA ligase (BadA) elucidate mechanism and expand substrate permissivity, C. K. Thornburg; S. Wortas-Strom; M. Nosrati; J. H. Geiger; K. D. Walker, Biochemistry, 2015, 54(40), 6230–6242. DOI: 10.1021/acs.biochem.5b00899
Ring‑substituted α‑arylalanines for probing substituent effects on the isomerization reaction catalyzed by an aminomutase, N.D. Ratnayake; N. Liu; L. A. Kuhn; K. D. Walker, ACS Catalysis, 2014, 4(9), 3077.
Genome sequencing and analysis of the paclitaxel-producing endophytic fungus Penicillium aurantiogriseum, Y. Yang; H. Zhao; R. A. Barrero; B. Zhang; G. Sun; I. W. Wilson; F. Xie; K. D. Walker; J. W. Parks; R. Bruce; et al., BMC Genomics, 2014, 15(1):69.
A bacterial tyrosine aminomutase proceeds through retention or inversion of stereochemistry to catalyze its isomerization reaction, U. Wanninayake; K.D. Walker, J. Am. Chem.Soc., 2013, 135(30), 11193.
Assessing the deamination rate of a covalent aminomutase adduct by burst phase analysis, U. Wanninayake; K.D. Walker, Biochemistry, 2012, 51(26), 5226.
Taxol biosynthesis: Tyrocidine synthetase A catalyzes the production of phenylisoserinyl CoA and other amino phenylpropanoyl thioesters, R. Muchiri; K.D. Walker, Chem. Biol., 2012, 19(6), 679.
Insights into the mechanistic pathway of the Pantoea agglomerans phenylalanine aminomutase, S. Strom; U. Wanninayake; N. D. Ratnayake; K. D. Walker; J. H. Geiger, Ang. Chem. Int. Ed., 2012, 51(12), 2898.
(S)-Styryl-α-alanine used to probe the intermolecular mechanism of an intramolecular MIO-aminomutase, U. Wanninayake; Y. Deporre; M. Ondari; K. D. Walker, Biochemistry, 2011, 50(46), 10082.
CV
Chemistry, Biochemistry, Molecular Biology, and Biocatalysis
B.S., 1988, Univ. of Washington
Research Chemist, 1988-1990, FDA (Bothell, WA)
Ph.D., 1997, Univ. of Washington
NIH Postdoc. Research Fellow, 1997-2000, Institute of Biological Chemistry, Washington State Univ.
Research Assistant Professor, 2000-2003, Institute of Biological Chemistry, Washington State Univ.
Curriculum Vitae (click here)
Awards
| Year | Award | Organization |
|---|---|---|
| 2021 | MTRAC AgBio Innovation Challenge Award | MSU Innovation Center |
| 2011 | Outstanding Graduate Advisor | |
| 2006 | Neish Young Investigator Award | Phytochemical Society of North America |
| 1997 | Ph.D. | University of Washington, Seattle |
| 1988 | Bachelor of Science | University of Washington, Seattle |