Abstract

Our preliminary results show that Fourier Transform Infrared Difference Spectroscopy can be used to study the state of the chromophore (retinal) and protein conformation in bacteriorhodopsin and its photocycle intermediates. We propose a three year research project to investigate both bacteriorhodopsin and visual pigments in the infrared region. Retinal analogs incorporated into the protein will be studied to provide information for the assignment of the infrared absorption bands and the nature of the processes that follow the absorption of light. Fourier Transform Infrared Difference Spectroscopy will also permit us to follow the kinetics of these systems at low temperatures. The extension of these studies to shorter times (10 Mus) will be done with suitable modifications on our existing diode laser system. Experiments in the visible region using a flash photolysis system and spectrophotometer will be carried out both as a control and to allow correlation of our infrared results with existing resonance Raman and visible data. These results combined with the theoretical calculations of our collaborators, should provide important information on the proton pumping mechanism of bacteriorhodopsin and the early processes in visual excitation.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
2R01GM032455-04
Application #
3281308
Study Section
Biophysics and Biophysical Chemistry B Study Section (BBCB)
Project Start
1983-01-01
Project End
1987-12-31
Budget Start
1986-01-01
Budget End
1986-12-31
Support Year
4
Fiscal Year
1986
Total Cost
Indirect Cost

  Institution

Name
University of Illinois Urbana-Champaign
Department
Type
DUNS #
041544081
City
Champaign
State
IL
Country
United States
Zip Code
61820

  Publications

Mourant, J R; Braunstein, D P; Chu, K et al. (1993) Ligand binding to heme proteins: II. Transitions in the heme pocket of myoglobin. Biophys J 65:1496-507
Steinbach, P J; Chu, K; Frauenfelder, H et al. (1992) Determination of rate distributions from kinetic experiments. Biophys J 61:235-45
Steinbach, P J; Ansari, A; Berendzen, J et al. (1991) Ligand binding to heme proteins: connection between dynamics and function. Biochemistry 30:3988-4001
Ormos, P (1991) Infrared spectroscopic demonstration of a conformational change in bacteriorhodopsin involved in proton pumping. Proc Natl Acad Sci U S A 88:473-7
Ormos, P; Ansari, A; Braunstein, D et al. (1990) Inhomogeneous broadening in spectral bands of carbonmonoxymyoglobin. The connection between spectral and functional heterogeneity. Biophys J 57:191-9
Hong, M K; Braunstein, D; Cowen, B R et al. (1990) Conformational substates and motions in myoglobin. External influences on structure and dynamics. Biophys J 58:429-36
Berendzen, J; Braunstein, D (1990) Temperature-derivative spectroscopy: a tool for protein dynamics. Proc Natl Acad Sci U S A 87:1-5
Xie, A H (1990) Quantum efficiencies of bacteriorhodopsin photochemical reactions. Biophys J 58:1127-32
Bagley, K A; Eisenstein, L; Ebrey, T G et al. (1989) A comparative study of the infrared difference spectra for octopus and bovine rhodopsins and their bathorhodopsin photointermediates. Biochemistry 28:3366-73
Zimanyi, L; Ormos, P; Lanyi, J K (1989) Low-temperature photoreactions of halorhodopsin. 1. Detection of conformational substates of the chromoprotein. Biochemistry 28:1656-61

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