Research interests
The main focus of my laboratory deals with the structural basis of allosteric control and its long term application to understanding control processes resulting from protein-ligand and protein-protein interactions. This research focuses on specific structural domains found in a wide variety of metabolic proteins and transcription regulators, the ACT and ASB domains, that interact with small molecules to affect the activity of the protein.
Major techniques utilized Include:
- Site-directed mutagenesis
- Transient kinetic analysis
- Fluorescence techniques
- X-ray crystallography
These studies are an integral step in the long term goals of this laboratory to determine the relationship between structure and function in conformationally regulated control mechanisms, to eventually relate that to the physiology and pathophysiology mediated by these enzymes and by analogous systems, and to eventually understand allosteric proteins well enough to be able to apply basic principles to more complex systems.

Gregory Grant, Xiao Lan Xu
Education
1971: Iowa State University, Ames, IA. B.S. Biochemistry
1975: University of Wisconsin, Madison, WI. Ph.D. Biochemistry
1975-78: Washington University, St. Louis, MO. Post-Doc. Protein Chemistry
Academic Positions
Sept.’78-June’80: Research Asst. Prof. of Biochemistry in Medicine, Department of Medicine (Dermatology)
July ’80-Aug.’82: Research Asst. Prof. of Biochemistry in Medicine and Biological Chemistry, Department of Medicine (Dermatology) and Department of Biological Chemistry
Sept.’82-Dec.’88: Assistant Professor of Biological Chemistry, and of Biochemistry in Medicine, Department of Biological Chemistry and Department of Medicine (Dermatology)
Sept.’82-Present: Director, Protein Chemistry Laboratory
Jan. ’89-Dec.’91: Associate Professor, Department of Biochemistry and Molecular Biophysics, and Department of Medicine
Jan.’92-June ’95: Associate Professor, Department Developmental Biology and Department of Medicine
July ’95 – Present: Professor, Department of Developmental Biology, and Department of Medicine
Selected publications
- Xu, X.L. and Grant, G. A. Determinants of Substrate Specificity in D-3-Phosphoglycerate Dehydrogenase. Conversion of the M. tuberculosis enzyme from one that does not use a-Ketoglutarate as a Substrate to one that does. Arch Biochem Biophys. 2019, 671, 218-224.
- Grant, G. A. (2018) D-3-Phosphoglycerate Dehydrogenase. Frontiers in Molecular Biosciences. 5, Article 110. Doi:10.3389/fmolb.2018.00110.
- Grant, G. A. The many faces of partial inhibition: Revealing imposters with graphical analysis. Arch Biochem Biophys. 2018, 653, 10-23.
- Grant, G. A. Elucidation of a self-sustaining cycle in E. coli L-serine biosynthesis that results in the conservation of the coenzyme, NAD+. Biochemistry. 2018, 57, 1798-1806, 10.1021/acs.biochem.8b00074.
- Grant, GA. The Regulatory mechanism of Mycobacterium tuberculosis phosphserine phosphatase serB2. Biochemistry. 2017, 56, 6481-6490.
- Xu XL, Grant GA. (2016) Mutagenic and chemical analyses provide new insight into enzyme activation and mechanism of the type 2 iron-sulfur l-serine dehydratase from Legionella pneumophila. Arch Biochem Biophys. 2016 Apr 15;596:108-17.
- Yan Y, Grant GA, Gross ML. (2015) Hydrogen-Deuterium Exchange Mass Spectrometry Reveals Unique Conformational and Chemical Transformations Occurring upon [4Fe-4S] Cluster Binding in the Type 2 L-Serine Dehydratase from Legionella pneumophila. Biochemistry. 2015 Sep 1;54(34):5322-8.
- Xu XL, Chen S, Salinas ND, Tolia NH, Grant GA. (2015) Comparison of Type 1 D-3-phosphoglycerate dehydrogenases reveals unique regulation in pathogenic Mycobacteria. Arch Biochem Biophys. 2015 Mar 15;570:32-9.
- Thoden JB, Holden HM, Grant GA. (2014) Structure of L-serine dehydratase from Legionella pneumophila: novel use of the C-terminal cysteine as an intrinsic competitive inhibitor. Biochemistry. 2014 Dec 9;53(48):7615-24.
- Xu XL, Grant GA. (2014) Regulation of Mycobacterium tuberculosis d-3-Phosphoglycerate Dehydrogenase by Phosphate-Modulated Quaternary Structure Dynamics and a Potential Role for Polyphosphate in Enzyme Regulation. Biochemistry. 2014 53 (26) 4239-4249.
- Xu XL, Grant GA. (2013) Identification and characterization of two new types of bacterial L-serine dehydratases and assessment of the function of the ACT domain. Arch Biochem Biophys. 540(1-2):62-9.
- Grant GA. (2012) Kinetic evidence of a noncatalytic substrate binding site that regulates activity in Legionella pneumophila L-serine dehydratase. Biochemistry. 51(35):6961-7.
- Chen S, Xu XL, Grant GA. (2012) Allosteric activation and contrasting properties of L-serine dehydratase types 1 and 2. Biochemistry. 51(26):5320-8.
- Grant GA. (2012) Contrasting catalytic and allosteric mechanisms for phosphoglycerate dehydrogenases. Arch Biochem Biophys. 519(2):175-85.
- Xu XL, Chen S, Grant GA. (2011) Kinetic, mutagenic, and structural homology analysis of L-serine dehydratase from Legionella pneumophila. Arch Biochem Biophys. 515(1-2):28-36.
- Grant GA. (2011) Transient kinetic analysis of L-serine interaction with Escherichia coli D-3-phosphoglycerate dehydrogenase containing amino acid mutations in the hinge regions. Biochemistry.12;50(14):2900-6.
- Burton, R. L., Chen, S., Xu, X. L., and Grant G. A. (2009) Transient Kinetic Analysis of L-Serine Interaction with E. coli D-3-Phosphoglycerate Dehydrogenase Reveals the Mechanism of V-type Regulation and the Order of Effector Binding, Biochemistry 48, 12242-12251.
- Burton, R. L., Chen, S., Xu, X. L., and Grant G. A. (2009) Role of the Anion-Binding Site in Catalysis and Regulation of Mycobacterium tuberculosis D-3-Phosphoglycerate Dehydrogenase, Biochemistry 48, 4808-4815.
- Burton, R. L., Hanes, J. W., and Grant, G. A. (2008) A stopped-flow kinetic analysis of substrate binding and catalysis in E. coli D-3-Phoshphoglycerate Dehydrogense, J. Biol. Chem. 283, 29706-29714.
- Dey, S., Burton, R. L., Grant, G. A., and Sacchettini, J. C. (2008) Structural analysis of substrate and effector binding in Mycobacterium tuberculosis D-3-Phosphoglycerate Dehydrogenase, Biochemistry 47, 8271-8282.
- Burton, R. L., Chen, S., Xu, X. L., and Grant G. A. (2007) A Novel Mechanism for Substrate Inhibition in Mycobacterium tuberculosis D-3-Phosphoglycerate Dehydrogenase. J. Biol. Chem. 282, 31493-31503.
- Dey, S., Hu, Z., Xu, X. L., Sacchettini, J. C., and Grant, G. A. (2007) The Effect of Hinge Mutations on Effector Binding and Domain Rotation in E. coli D-3-Phosphoglycerate Dehydrogenase. J. Biol. Chem. 282, 18418-18426.
- Grant, G. A., Hu, Z., and Xu, X. L. (2005) Identification of Amino Acid Residues Contributing to the Mechanism of Cooperativity in Escherichia coli D-3-Phosphoglycerate Dehydrogenase. Biochemistry 44, 16844-16852.
- Thompson, J. R., Bell, J. K., Bratt, J., Grant, G. A., and Banaszak, L. J. (2005) Vmax Regulation Through Domain and Subunit Changes. The Active Form of Phosphoglycerate Dehydrogenase. Biochemistry 44, 5763-5773.
- Dey, S., Grant, G. A., and Sacchettini, J. C. (2005) Crystal Structure of Mycobacterium tuberculosis D-3-Phosphoglycerate Dehydrogenase: Extreme Asymmetry in a Tetramer of Identical Subunits. J. Biol. Chem, 280, 14892-14899.
- Dey, S., Hu, Z., Xu, X. L., Sacchettini, J. C., and Grant, G. A. (2005) D-3-Phosphoglycerate Dehydrogenase from Mycobacterium Tuberculosis is a Link Between the E. coli and Mammalian Enzymes. J. Biol. Chem. 280, 14884-14891.