Structure and dynamics of the ATP synthase and other molecular machines.
Richter Research Synopsis:
ATP synthase Structure and Function
The F1FO-ATP synthase is a tiny molecular rotary motor driven by binding and hydrolysis of ATP in one direction and by trans-membrane proton flux in the other direction. This complex multi-subunit protein generates sufficient torque to propel large (1-2 micrometers) actin filaments through solution with a remarkably high energy conversion efficiency. The photosynthetic ATP synthase of higher plants has several unique properties that separate it from its mitochondrial and bacterial counterparts and that offer unique inroads to examine the mechanism of energy coupling. One such property is the presence of a special regulatory domain in the γ subunit of higher plant species which, via the reversible oxidation/reduction of an intrinsic dithiol that governs an interaction with the inhibitory ε subunit, provides a molecular "switch" mechanism that tightly controls the catalytic activity of the enzyme. The principle goal of the proposed research is to identify the productive binding interactions between the γ and ε subunits, and between these two subunits and the other F1 subunits, that are involved in the molecular "switch" mechanism. The information to be gained from this work is likely to prove seminal in understanding natural processes that have evolved to gate the motor, in identifying the mechanism of elastic coupling between the FO and F1 segments, and in designing gated nanodevices for future industrial and biomedical applications. Ongoing projects involve: protein engineering, folding and ATPase complex assembly; NMR and crystallization studies of subunit structure; single molecule enzyme analysis using atomic force microscopy, fluorescence and dark-field microscopy; and surface patterning for on-chip fabrication of nanodevices to address industrial and biomedical needs.
1) Examination of ecto-enzyme complexes associated with the plasma membranes of endothelial and cancer cells; 2) Fluorescence nucleotide and protein-protein binding studies of mammalian G proteins and adenylyl cyclase; 3) Targeting the Hsp90 multichaperone complex for cancer therapy; and 4) Targeting novel cathepsin D-like proteases as therapeutic targets for Leishmanias, tropical diseases caused by Trypanosome parasites.
Selected Publications —
- Buchert, F., Schober, Y., Rompp, A., Richter, M.L. and Forreiter, C. 2012 ”Reactive oxygen species affect ATP hydrolysis by targeting a highly conserved amino acid cluster in the thylakoid ATP synthase g subunit” Biochem.Biophys.Acta 1817, 2038-2048.
- Schuler, D., Lubker, C., Lushington, G.H., Tang, W-J., Shen, Y., Richter, M., Seifert, R. 2012 “Interactions of Bordetella pertussis adenylyl cyclase toxin CyaA with calmodulin mutants and calmodulin antagonists: Comparison with membranous adenylyl cyclase I” Biochemical Pharmacology 83, 839-848
- Pinto, C., Lushington, G.H., Richter, M.L., Gille, A., Geduhn, J., König, B., Mou, T-C., Sprang, S. and Seifert, R. 2011 “Structure-activity relationships for the interactions of 2’- and 3’-(0)-(N-methyl)anthraniloyl-subtituted purine and pyrimidine nucleotides with mammalian adenylyl cyclases” Biochemical Pharmacology 82, 358-370.
- Rankin, C.A., Roy, A., Zhang, Y. and Richter, M.L. 2011 “Parkin, a top level manager in the cell’s Sanitation Department” Open Biochemistry Journal 9-26.
- Colvert,K.K. Gao, F., Zheng, D., Mehta, S. and Richter, M.L. 2010 “The Mutation E242K in the chloroplast ATP synthase Gamma Subunit Increases the Inhibitory Binding of the Epsilon Subunit Without Changing the Apparent Redox Potential of the Regulatory Dithiol” C.Lu (Ed.) Photosynthesis: Research for Food, Fuel and Future—15th International Conference on Photosynthesis, Zhejiang University Press, Springer-Verlag GmbH.
- Bishop, S.C., Mehta, S., Colvert, K.K., Zheng, D., Richter, M.L., Berrie, C.L. and Gao, F. 2010 “Insertion of a rigid structural element into the regulatory domain of the chloroplast F1-ATPase gamma subunit for rotational studies” C.Lu (Ed.) Photosynthesis: Research for Food, Fuel and Future—15th International Conference on Photosynthesis, Zhejiang University Press, Springer-Verlag GmbH.
- Suryanarayana, S., Pinto, C., Mou, T-C., Richter, M.L., Lushington, G.H. and Seifert, R, 2009 “The C1 Homodimer of Adenylyl Cyclase Binds Nucleotides with High Affinity but Possesses Exceedingly Low Catalytic Activity” Neuroscience Letters 467, 1-5.
- Pinto, C., Hübner, M., Gille, A., Richter, M.L. Mou, T-C. and Sprang, S.R. Seifert, R. 2009 ”Differential Interactions of the Catalytic Subunits of Adenylyl Cyclase with Forskolin Analogs” Biochem. Pharmacol., 78, 62-69.
- Suryanarayana, S., Gottle, M., Gille, A., Mou, T-C., Richter, M.L. and Seifert, R. 2009 “Differential inhibition of various adenylyl cyclase isoforms and soluble guanylyl cyclase by 2’,3’-O-(2,4,6-trinitrophenyl)-substituted nucleoside 5’-triphoshates” J.Pharmacol.Exptl.Therap. 330,687-695.
- Suryanarayana S, Wang JL, Richter M, Shen Y, Tang WJ, Lushington GH, Seifert R. 2009 “Distinct interactions of 2'- and 3'-O-(N-methyl)anthraniloyl-isomers of ATP and GTP with the adenylyl cyclase toxin of Bacillus anthracis, edema factor” Biochem Pharmacol. 2009 Aug 1;78(3):224-30.
- Samra, H.S., He, F., Degner, N.R., and Richter, M.L. 2008 “The role of specific beta-gamma subunit interactions in oxyanion stimulation of the MgATP hydrolysis of a hybrid photosynthetic F1-ATPase”
- Bioenergetics & Biomembranes 40, 69-76.
- He, F., Samra, H.S., Johnson, E.A., Degner, N.R., McCarty, R.E. and Richter, M.L. 2008 “C-terminal mutations in the chloroplast ATP synthase gamma subunit impair ATP synthesis and stimulate ATP hydrolysis” Biochemistry, 47, 836-844.
- He, F., Samra, H.S., Tucker, W.C., Mayans, D.R., Huang, E., Gromet-Elhanan, Z., Berrie, C.L. and Richter, M.L. 2007 “Mutations within the C-terminus of the gamma subunit of the photosynthetic F1-ATPase activate MgATP hydrolysis and attenuate the stimulatory oxyanion effect” Biochemistry 46, 2411-2418.
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