The long term goals of this research include the development of methodology to permit the folding, flexibility and dynamics of protein structure to be interrogated, and the development and use of fluorescent probes in novel ways to enhance our understanding of protein structure, dynamics and function. During the five years of proposed research, the focus of efforts will be on study of the mechanism of modified DHFRs through steady state, pre-steady state and single molecule kinetic studies. Fluorescence spectroscopy will be used to study the protein conformational changes and their association with the key steps in DHFR catalysis.

Public Health Relevance

The present project is aimed at describing and quantifying the particular sequence, structural and dynamic properties that operate to enhance enzymatic catalysis. The proposed studies will provide important insights into enzyme function and will foster protein design and drug discovery efforts. The enzyme DHFR, which is the target of important antineoplastic and antimicrobial drugs, will be the focus of our efforts.

National Institute of Health (NIH)
National Institute of General Medical Sciences (NIGMS)
Research Project (R01)
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Macromolecular Structure and Function E Study Section (MSFE)
Program Officer
Lewis, Catherine D
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Arizona State University-Tempe Campus
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United States
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Talukder, Poulami; Chen, Shengxi; Roy, Basab et al. (2015) Cyanotryptophans as Novel Fluorescent Probes for Studying Protein Conformational Changes and DNA-Protein Interaction. Biochemistry 54:7457-69
Hanoian, Philip; Liu, C Tony; Hammes-Schiffer, Sharon et al. (2015) Perspectives on electrostatics and conformational motions in enzyme catalysis. Acc Chem Res 48:482-9
Liu, C Tony; Francis, Kevin; Layfield, Joshua P et al. (2014) Escherichia coli dihydrofolate reductase catalyzed proton and hydride transfers: temporal order and the roles of Asp27 and Tyr100. Proc Natl Acad Sci U S A 111:18231-6
Talukder, Poulami; Chen, Shengxi; Arce, Pablo M et al. (2014) Efficient asymmetric synthesis of tryptophan analogues having useful photophysical properties. Org Lett 16:556-9
Talukder, Poulami; Chen, Shengxi; Liu, C Tony et al. (2014) Tryptophan-based fluorophores for studying protein conformational changes. Bioorg Med Chem 22:5924-34
Liu, C Tony; Layfield, Joshua P; Stewart 3rd, Robert J et al. (2014) Probing the electrostatics of active site microenvironments along the catalytic cycle for Escherichia coli dihydrofolate reductase. J Am Chem Soc 136:10349-60
Liu, C Tony; Wang, Lin; Goodey, Nina M et al. (2013) Temporally overlapped but uncoupled motions in dihydrofolate reductase catalysis. Biochemistry 52:5332-4
Chen, Shengxi; Fahmi, Nour Eddine; Bhattacharya, Chandrabali et al. (2013) Fluorescent biphenyl derivatives of phenylalanine suitable for protein modification. Biochemistry 52:8580-9
Chen, Shengxi; Fahmi, Nour Eddine; Wang, Lin et al. (2013) Detection of dihydrofolate reductase conformational change by FRET using two fluorescent amino acids. J Am Chem Soc 135:12924-7
Bozeman, Trevor C; Nanjunda, Rupesh; Tang, Chenhong et al. (2012) Dynamics of bleomycin interaction with a strongly bound hairpin DNA substrate, and implications for cleavage of the bound DNA. J Am Chem Soc 134:17842-5

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