Dr. Ludwig Brand
Joint Appointed Faculty
Professor, Biology

Johns Hopkins University
Department of Biology
3400 North Charles Street
224 Mudd Hall
Baltimore, MD 21218
410-516-7298 Office
410-516-5213 Fax
ludwig.brand@jhu.edu

Spectroscopic Studies of the Structure and Function of Biological Macromolecules

Our laboratory is interested in the dynamic structure and function of proteins, nucleic acids, glyco-conjugates, and membranes. Motions and interactions that occur on time scales from picoseconds to minutes are investigated. Fluorescence spectroscopy provides a relatively non-invasive probe and has the power to examine functional macromolecular assemblies both in solution and in the intact cell. The current interest is in the dynamics of electrostatic interactions in proteins. We are approaching this problem with the aid of time-resolved fluorescence emission studies. Nanosecond time-resolved spectral shifts of both the intrinsic and/or extrinsic emission may be related to the time dependence of changes in the electric field around the fluorophore. Proteins being studied include the galactose repressor, interlukin II, staphylococcal. Nuclease and several proteins involved in the bacterial phosphoenol pyruvate glucose transfer system. The work with the PTS system is done in collaboration with Professor S. Roseman.

Selected Publications:

• Toptygin, D., A.M. Gronenborn, and L. Brand. (2006) Nanosecond relaxation dynamics of protein GB1 identified by the time-dependent red shift in the fluorescence of tryptophan and 5-fluorotryptophan. J. Phys. Chem. B 110:26292-26302.
• Xu, J., D. Toptygin, K.J. Graver, R.A. Albertini, R.S. Savchenko, N.D. Meadow, S. Roseman, P.R. Callis, L. Brand, and J.R. Knutson. (2006) Ultrafast fluorescence dynamics of tryptophan in the proteins monellin and IIAGlc. J. Am. Chem. Soc. 128:1214-1221.
• Zheng, Y., F. Mamdani, D. Toptygin, L. Brand, J.T. Stivers, and P.A. Cole. (2005) Fluorescence analysis of a dynamic loop in the PCAF/GCN5 histone acetyltransferase. Biochemistry 44:10501-10509.
• Toptygin, D., R.S. Savichenko, N.D. Meadow, and L. Brand. (2001) Homogeneous spectrally and time-resolved fluorescence emission from single-tryptophan of IIAGlc protein. J. Phys. Chem. B 105:2043-2055.
• Toptygin, D., and L. Brand. (2000) Spectrally and time-resolved fluorescence emission of indole during solvent relaxation: a quantitative model. Chem. Phys. Lett. 322:496-502.