REBEKKA WACHTER

Research and Teaching Interests

Our research is focused on elucidating the structure and function of proteins, with particular emphasis on fluorescent proteins and remodeling enzymes. The ultimate goal is to introduce novel biochemical, optical, or functional features into a protein’s scaffold. We utilize macromolecular X-ray crystallography to determine atomic-resolution structures, steady-state spectroscopy to investigate protein maturation kinetics, ultra-fast spectroscopy to examine the photochemistry of intrinsic chromophores, and molecular biology for protein engineering purposes.

• Protein self-processing reactions
  In fluorescent proteins such as GFP, the biosynthesis of several chemically distinct chromophores involves self-catalysis of peptide cyclization and oxidation reactions. Our research aims to develop step-by-step mechanistic models for the amino acid derivatizations that occur spontaneously upon protein folding, yielding brightly colored fluorophores from a single gene product.
  
  
• Structural basis of color evolution in fluorescent proteins
  Four color classes (cyan, green, yellow, red) have evolved repeatedly and independently along different lineages of GFP-like proteins. We aim to understand how conformational remodeling facilitates phenotypic changes such as color switching events during protein evolution.
  
  
• Bioenergy and photosynthesis
  The regulation of carbon fixation in higher plants and green algae includes remodeling enzymes responsible for maintaining the activity of RuBisCo, which catalyzes the central carboxylation reaction. We are interested in determining the mechanism of action of these auxiliary factors, as they appear to limit the net rate of CO₂ fixation at elevated temperatures.
  
  
• Biomedical
  We are investigating the structural and biochemical properties of M. tuberculosis protein factors with proposed roles in the regulation of MTB virulence.

Representative Publications

"Chromogenic Cross-link Formation in Green Fluorescent Protein ," Wachter, R. M., Acc. Chem. Res. 40, 120-127 (2007).

"X-ray Structure of Cerulean GFP: A Tryptophan-Based Chromophore Useful for Fluorescence Lifetime Imaging," Malo, G. D., Pouwels, L. J., Wang, M., Weichsel, A., Montfort, W. R., Rizzo, M. A., Piston, D. W., Wachter, R. M., Biochemistry (Accelerated Publication) 46, 9865-9873 (2007).

"Reaction Progress of Chromophore Biogenesis in Green Fluorescent Protein," Zhang, L., Patel, H. N., Lappe, J. W., Wachter, R. M., J. Am. Chem. Soc. 128, 4766-4772 (2006).

"The family of GFP-like proteins: Structure, Function, Photophysics and Biosensor Applications," Wachter, R. M., Photochem. Photobiol. 82, 339-344 (2006).

"Maturation Efficiency, Trypsin Sensitivity and Optical Properties of Arg96, Glu222 and Gly67 Variants of Green Fluorescent Protein.," J.A. Sniegowski, M.E. Phail and R.M. Wachter, Biochem. Biophys. Res. Comm 332, 657-663 (2005).

"Oxidative Chemistry in the GFP Active Site Leads to Covalent Cross-Linking of a Modified Leucine Side Chain with a Histidine Imidazole: Implications for the Mechanism of Chromophore Formation," M.A. Rosenow, H.N. Patel and R.M. Wachter, Biochemistry 44, 8303-8311 (2005).

"Base-catalysis of Chromophore Fromation in Arg96 and Glu222 variants of Green Fluorescent Protein," J.A. Sniegowski, J.W. Lappe, H.N. Patel, H.A. Huffman and R.M. Wachter, J. Biol. Chem 280, 26248-26255 (2005).

"zFP538, a Yellow Fluorescent Protein from Zoanthus, Contains a Novel Three-Ring Chromophore," S.J. Remington, R.M. Wachter, D.K. Yarbrough, B.P. Branchaud, D.C. Anderson, K. Kallio and K.A. Lukyanov, Biochemistry 44, 202-212 (2005).

"X-ray diffraction analysis and molecular replacement solution of the cyan fluorescent protein dsFP483," M. Wang, H.N. Patel and R. Wachter, Acta Cryst. 61, 922-924 (2005).

"Development and Characterization of Green Fluorescent Protein Mutants with Altered Lifetimes," Scruggs, A. W., Flores, C. L., Wachter, R. M., Woodbury, N. W. , Biochemistry 44, 13377- 13384 (2005).

"The Crystal Structure of the Y66L Variant of Green Fluorescent Protein Supports a Cyclization-Oxidation-Dehydration Mechanism for Chromophore Maturation.," M.A. Rosenow, H.A. Huffman, M.E. Phail and R.M. Wachter, Biochemistry 43, 4464-4472 (2004).

"Light Driven Decarboxylation of Wild-Type Green Fluorescent Protein.," Bell, A. F., Stoner-Ma, D., Wachter, R. M., Tonge, P. J. , J. Am. Chem. Soc. 125, 6919-6926 (2003).