The Drennan laboratory uses X-ray crystallography as the chief tool for investigating the structure and function of enzymes that are medically important or valuable in environmental remediation. We are particularly interested in metalloprotein biochemistry and in the role of conformational change in catalysis. Representative projects are described below.

Metalloenzymes & Medicine
Ribonucleotide reductases (RNRs) catalyze an essential step in DNA biosynthesis, the conversion of ribonucleotides to deoxyribonucleotides. RNR inhibition reduces cellular pools of deoxynucleoside triphosphates (dNTPs) and consequently impairs DNA biosynthesis and repair. As a result of these activities, RNRs are being pursued as targets for antiviral and antitumor therapies. To provide a molecular understanding of the catalytic and allosteric regulatory enzyme mechanisms, we are carrying out crystallographic studies of the simplest members of the RNR family (class II RNRs).

Metalloenzymes & the Environment
Carbon monoxide dehydrogenases (CODHs) play an important role in reducing levels of toxic CO gas in our environment. An estimated 108 tons of CO are removed annually from the earth and lower atmosphere by bacteria. A better understanding of the structure and mechanism of Ni-Fe-S-dependent carbon monoxide dehydrogenases could lead to development of biomimetic catalysts to lower CO levels in heavily polluted regions.

Metal Uptake & Metallocluster Assembly
Trace metals are essential for life. Organisms must obtain sufficient quantities of trace metals for growth, while also preventing the accumulation of excess metal that can be toxic to the cell. Our laboratory wants to understand the regulation of cellular metal uptake, and the cellular assembly of metallocofactors. We have begun our studies by investigating Ni uptake in E. coli, and Fe-S cluster assembly in Synechocystis.

Kung, Y., Ando, N., Doukov, T.I., Blasiak, L.C., Bender, G., Seravalli, J., Ragsdale, S.W., and Drennan, C.L. (2012) Visualising molecular juggling within a B₁₂-dependent methyltransferase complex, Nature DOI: 10.1038/nature10916.

Dowling, D.P., Croft, A.K., Drennan, C.L. (2012) Radical Use of Rossmann and TIM Barrel Architectures for Controlling Coenzyme B₁₂ Chemistry, Annu. Rev. Biophys. DOI: 10.1146/annurev-biophys-050511-102225.

Ando, N., Brignole, E. J., Zimanyi, C.M., Funk, M.A., Yokoyama. K., Asturias, F.J., Stubbe, J., and Drennan, C.L. (2011) Structural interconversions modulate activity of E. coli ribonucleotide reductase, Proc. Natl. Acad. Sci. U.S.A. DOI:10.1073/pnas.1112715108.

Anderson, W.A., et al (2011) Competencies: A Cure for Pre-Med Curriculum, Science 11, 760-761.

Setser, J.W., Lingaraju, G.M., Davis, C.A., Samson, L.D.,, and Drennan, C.L. (2011) Searching for DNA lesions: Structural evidence for lower and higher-affinity DNA binding conformations of human alkyladenine DNA glycosylase (AAG), Biochemistry DOI:10.1021/bi201484k.

Hamill, M., Jost, M., Wong, C., Elliott, S.J., Drennan, C.L. (2011) Flavin-induced oligomerization in Escherichia coli adaptive response protein AidB, Biochemistry 50, 10159–10169.

Firer-Sherwood, M., Ando, N., Drennan, C.L., and Elliott, S.J. (2011) Solution-based Structural Analysis of the Decaheme Cytochrome, MtrA, by Small Angle X-Ray Scattering and Analytical Ultracentrifugation, J. Phys. Chem. B,115, 11208–11214.

Yun, D., Dey, M., Higgins, L.J., Yan, F., Liu, H.W., and Drennan, C.L. (2011) Structural basis of regiospecificity of a mononuclear iron enzyme in antibiotic fosfomycin biosynthesis, J. Am. Chem. Soc. 133, 11262–11269.

Vey, J.L. and Drennan, C.L. (2011) Structural insights into radical generation by the Radical SAM superfamily, Chem. Rev. 111, 2487–2506.

Lingaraju, G.M., Davis, C.A., Setser, J.W., Samson, L.D.,, and Drennan, C.L. (2011) Structural basis for the inhibition of human alkyladenine DNA glycosylase (AAG) by 3,N⁴-ethenocytosine containing DNA, J. Biol. Chem., DOI: 10.1074/jbc.M110.192435.

Anderson, W.A., Banerjee, U., Drennan, C.L., Elgin, S.C., Epstein, I.R., Handelsman, J., Hatfull, G.F., Losick, R., O’Dowd, D.K., Olivera, B.M., Strobel, S.A., Walker, G.C., Warner, I.M. (2011) Changing the culture of science education at research universities. Science 331, 152–153.

Kung, Y. and Drennan, C.L. (2011) A role for nickel-iron cofactors in biological carbon monoxide and carbon dioxide utilization, Curr. Opin. Chem. Biol. 15, 276-283.

Li, D., Delaney, J., Page, C., Chen, A., Wong, C., Drennan, C.L., Essigmann, J.M. (2010)
Repair of DNA alkylation damage by the Escherichia coli adaptive response protein AlkB as studied by ESI-TOF mass spectrometry, J. Nucleic Acids 2010, Article ID 369434.

Drennan, C.L. (2010) In the nickel of time. Nat. Chem. 2, 900.

Phillips, C.M., Schreiter, E.R., Stultz, C.M. and Drennan, C.L (2010) Structural Basis of Low Affinity Nickel Binding to the Nickel-Responsive Transcription Factor NikR from Escherichia coli, Biochemistry 49, 7830–7838.

Phillips, C.M., Stultz, C.M. and Drennan, C.L (2010) Searching for the nik Operon: How a Ligand-responsive Transcription Factor Hunts for its DNA Binding Site, Biochemistry 49, 7757–7763.

Taylor, E.V., Fortune, J.A., Drennan, C.L. (2010) A Research-inspired Laboratory Sequence Investigating Acquired Drug Resistance, Biochem. Mol. Biol. Educ. 38, 247-252.

Taylor, E.V., Mitchell, R., Drennan, C.L. (2009) Creating an Interdisciplinary Introductory Chemistry Course without Time-Intensive Curriculum Changes, ACS Chem. Biol. 4, 979-982.

Kulik, H.J., Blasiak, L.C., Marzari, N., Drennan, C.L. (2009) First Principles Study of Non-heme Fe(II) Halogenase SyrB2 Reactivity, J. Am. Chem. Soc. 131, 14426–14433.

Drennan, C.L. and Jarrett, J.T. (2009) From Single Molecules to Whole Organisms: the Evolving Field of Mechanistic Enzymology, Curr. Opin. Chem. Biol. 13, 433-435.

Kung, Y., Doukov, T.I., Seravalli, J., Ragsdale, S.W., Drennan, C.L. (2009) Crystallographic Snapshots of Cyanide- and Water-Bound C-Clusters from Bifunctional Carbon Monoxide Dehydrogenase/Acetyl-CoA Synthase, Biochemistry 48, 7432-7440.

Phillips, C.M., Nerenberg, P.S., Drennan, C.L., and Stultz, C.M. (2009) Physical Basis of Metal-Binding Specificity in Escherichia coli NikR, J. Am. Chem. Soc. 131, 10220-10228.

Taylor, E.V., Mitchell, R., Drennan, C. (2009) A TA Training Bootcamp Reinforces Curriculum Innovations and Improves the Recitation Experience in Freshman Chemistry, MIT Faculty Newsletter XXI No. 4, 22-24.

Wong, C., Fujimori, D.G., Walsh, C.T., and Drennan, C.L. (2009) Structural Analysis of an Open Active Site Conformation of Non-heme Iron Halogenase CytC3, J. Am. Chem. Soc. 131, 4872-4879.

Ryan, K.S. and Drennan, C.L. (2009) Divergent pathways in the biosynthesis of bisindole natural products, Chem. Biol. 16, 351-264.

Blasiak, L.C. and Drennan, C.L. (2008) Structural Perspective on Enzymatic Halogenation, Acc. Chem. Res. 42, 147-155.

Vey, J. L., Yang, J., Li M., Broderick, W. E., Broderick, J. B., Drennan, C. L. (2008) Structural basis for glycyl radical formation by pyruvate formate-lyase activating enzyme, Proc. Natl. Acad. Sci. U.S.A. 105, 16137-16141.

Ryan, K.S., Chakraborty, S., Howard-Jones, A.R., Walsh, C.T., Ballou, D.P., and Drennan, C.L. (2008) The FAD Cofactor of RebC Shifts to an IN Conformation upon Flavin Reduction, Biochemistry 47, 13506-13513.

Hernandez, H. H., Jaquez, O. A., Hamill, M. J., Elliott, S. J., and Drennan, C. L. (2008) Thioredoxin Reductase from Thermoplasma acidophilum: A New Twist on Redox Regulation, Biochemistry 47, 9728-9737.

Hamill, M. J., Chobot, S. E., Hernandez, H. H., Drennan, C. L., and Elliott, S. J. (2008) Direct Electrochemical Analyses of a Thermophilic Thioredoxin Reductase: Interplay between Conformational Change and Redox Chemistry, Biochemistry 47, 9738-9746.

Doukov, T.I., Blasiak, L.C., Seravalli, J., Ragsdale, S.W., and Drennan, C.L. (2008) Xenon In and at the End of the Tunnel of Bifunctional Carbon Monoxide Dehydrogenase/Acetyl-CoA Synthase, Biochemistry 47, 3474-3483.

Ryan, K.S., Balibar, C.J., Turo, K.E., Walsh, C.T., and Drennan, C.L. (2008) The Violacein Biosynthetic Enzyme VioE Shares a Fold with Lipoprotein Transporter Proteins, J. Biol. Chem. 283, 6467-6475.

Phillips, C.M., Schreiter, E.R., Guo, Y., Wang, S.C., Zamble, D.B., and Drennan, C.L. (2008) Structural Basis of Metal Specificity for Nickel Regulatory Protein NikR, Biochemistry 47,1938-1946.

Taylor, E.V. and Drennan, C.L. (2007) Bringing the Excitement of Biological Research into the Chemistry Classroom at MIT, ACS Chem. Biol. 2, 515-517.

Schreiter, E.R. and Drennan, C.L. (2007) Ribbon-Helix-Helix Transcription Factors: Variations on a Theme, Nat. Rev. Microbiol. 5, 710–720.

Drennan, C.L. and Tolman, W. B. (2007) New Vistas in Bioinorganic Chemistry, Curr. Opin. Chem. Biol. 11, 113–114.

Hubbard, P.A., Padovani, D., Labunska, T., Mahlstedt, S.A., Banerjee, R., and Drennan. C.L., (2007) Crystal Structure and Mutagenesis of the Metallochaperone MeaB: Insight into the Causes of Methylmalonic Aciduria, J. Biol. Chem. 282, 31308-31316.

Ryan, K.S., Howard-Jones, A.R., Hamill, M.J., Elliott, S.J., Walsh, C.T., and Drennan, C.L., (2007) Crystallographic Trapping in the Rebeccamycin Biosynthetic Enzyme RebC, Proc. Natl. Acad. Sci. U.S.A. 104, 15311-15316.

Chobot, S.E., Hernandez, H.H., Drennan, C.L., and Elliott, S.J., (2007) Direct Electrochemical Characterization of Archaeal Thioredoxins, Angew. Chem., Int. Ed. 46, 4145-4147.

Doukov, T.I, Hemmi, H., Drennan, C.L., and Ragsdale, S.W. (2007) Structural and Kinetic Evidence for an Extended Hydrogen Bonding Network in Catalysis of Methyl Group Transfer: Role of an Active Site Asparagine Residue in Activation of Methyl Transfer by Methyltransferases, J. Biol. Chem. 282, 6609-6618.

Yeh, E., Blasiak, L.C., Koglin, A., Drennan, C.L., and Walsh, C.T. (2007) Chlorination by a Long-lived Intermediate in the Mechanism of Flavin-dependent Halogenases, Biochemistry 46, 1284-1292.

Frick, L.E., Delaney, J.C., Wong, C., Drennan, C.L., and Essigmann, J.M. (2007) Alleviation of 1,N⁶-Ethanoadenine Genotoxicity by the Escherichia coli Adaptive Response Protein AlkB, Proc. Natl. Acad. Sci. U.S.A. 104, 755-760.

Schreiter, E.R., Wang, S. C., Zamble, D.B., and Drennan, C.L. (2006) NikR-operator Complex Structure and the Mechanism of Repressor Activation by Metal Ions, Proc. Natl. Acad. Sci. U.S.A. 103, 13676-13681.

Blasiak, L.C., Vaillancourt, F.H., Walsh, C.T., and Drennan, C.L. (2006) Crystal Structure of the Non-haem Iron Halogenase SyrB2 in Syringomycin Biosynthesis, Nature 440, 368-371.

Delaney, J.C., Smeester, L., Wong, C., Frick, L. E., Taghizadeh, L., Wishnok, J. S., Drennan, C. L., Samson, L. D., and Essigmann, J. M. (2005) AlkB Reverses Etheno DNA Lesions Caused by Lipid Oxidation in vitro and in vivo, Nat. Struct. Mol. Biol. 12, 855-860.

Higgins, L. J., Yan, F., Liu P., Liu, H.-W., and Drennan, C. L. (2005) Structural Insight into Antibiotic Fosfomycin Biosynthesis by a Mononuclear Iron Enzyme, Nature 437, 838–844.

Berkovitch F., Behshad, E., Kuo-Hsiang Tang, K-H., Enns, E.A., Frey, P.A., and Drennan, C.L. (2004) A Locking Mechanism Preventing Radical Damage in the Absence of Substrate, as Revealed by the X-ray Structure of Lysine 5,6-Aminomutase, Proc. Natl. Acad. Sci. U.S.A. 101, 15870–15875.

Midelfort, K.S., Hernandez, H.H., Lippow, S.M., Tidor, B., Drennan, C.L., and Wittrup, K.D. (2004) Substantial Energetic Improvement with Minimal Structural Perturbation in a High Affinity Mutant Antibody, J. Mol. Biol. 343, 685–701.

Tirupati, B., Vey, J.L., Drennan, C.L., and Bollinger, J.M. Jr. (2004) Kinetic and Structural Characterization of Slr0077/SufS, the Essential Cysteine Desulfurase from Synechocystis sp. PCC 6803, Biochemistry 43, 12210–12219.

Nicolet, Y., and Drennan, C.L. (2004) AdoMet Radical Proteins – from Structure to Evolution – Alignment of Divergent Protein Sequences Reveals Strong Secondary Structure Element Conservation, Nucleic Acids Res. 32, 4015–4025.

Berkovitch, F., Nicolet, Y., Wan, J.T., Jarrett, J.T., and Drennan, C.L. (2004) The Crystal Structure of Biotin Synthase, an S-Adenosylmethionine-Dependent Radical Enzyme, Science 303, 76–79.

Schreiter, E.R., Sintchak, M.D., Guo, Y., Chivers, P.T., Sauer, R.T., and Drennan, C.L. (2003) Crystal Structure of the Nickel-Responsive Transcription Factor NikR, Nat. Struct. Biol. 10, 794–799.

Doukov, T.I., Iverson, T.M., Seravalli, J., Ragsdale, S.W., and Drennan, C.L. (2002) A Ni-Fe-Cu Center in a Bifunctional Carbon Monoxide Dehydrogenase/Acetyl-CoA Synthase, Science 298, 567–572.

Sintchak, M.D., Arjara, G., Kellogg, B.A., Stubbe, J., and Drennan, C.L. (2002) The Crystal Structure of Class II Ribonucleotide Reductase Reveals How an Allosterically Regulated Monomer Mimics a Dimer, Nat. Struct. Biol. 9, 293–300.

Drennan, C.L., Heo, J., Sintchak, M.D., Schreiter, E., and Ludden, P.W. (2001) Life on Carbon Monoxide: X-ray Structure of Rhodospirillum rubrum Ni-Fe-S Carbon Monoxide Dehydrogenase, Proc. Natl. Acad. Sci. U.S.A. 98, 11973–11978.