Trapping the M sub 1 and M sub 2 substrates of bacteriorhodopsin for electron diffraction studies

Technical Report · Fri May 01 00:00:00 EDT 1992

DOI:https://doi.org/10.2172/5118357· OSTI ID:5118357

Perkins, G A

Visible and Fourier transform infrared (FTIR) absorption spectroscopies are used to observe protein conformational changes occuring during the bacteriorhodopsin photocycle. Spectroscopic measurements which define the conditions under which bacteriorhodopsin can be isolated and trapped in two distinct substates of the m intermediate of the photocycle, M{sub 1}, and M{sub 2}, are described. A protocol that can be used for high-resolution electron diffraction studies is presented that will trap glucose-embedded purple membrane in the M{sub 1}and M{sub 2} substates at greater than 90% concentration. It was discovered that glucose alone does not provide a fully hydrated environment for bacteriorhodopsin. Equilibration of glucose-embedded samples at high humidity can result in a physical state that is demonstrably closer to the native, fully hydrated state. An extension of the C-T Model of bacteriorhodopsin functionality (Fodor et al., 1988; Mathies et al., 1991) is proposed based on FTIR results and guided by published spectra from resonance Raman and FTIR work. 105 refs.

• Research Organization: Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE; DOHHS; USDOE, Washington, DC (United States); Department of Health and Human Services, Washington, DC (United States)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 5118357
• Report Number(s): LBL-32304; ON: DE92016906
• Resource Relation: Other Information: Thesis (Ph.D.)
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
59 BASIC BIOLOGICAL SCIENCES
PHOTOSYNTHETIC BACTERIA
ABSORPTION SPECTROSCOPY
RHODOPSIN
ELECTRON DIFFRACTION
EXCITED STATES
FOURIER TRANSFORM SPECTROMETERS
COHERENT SCATTERING
DIFFRACTION
ENERGY LEVELS
MEASURING INSTRUMENTS
ORGANIC COMPOUNDS
PIGMENTS
PROTEINS
SCATTERING
SPECTROMETERS
SPECTROSCOPY
140505* - Solar Energy Conversion- Photochemical
Photobiological
& Thermochemical Conversion- (1980-)
550200 - Biochemistry