TY  - JOUR
AU  - Efremov, R.
AU  - Gordeliy, V. I.
AU  - Heberle, J.
AU  - Büldt, G.
TI  - Time-resolved microscopy on a single crystal of bacteriorhodopsin reveals lattice induced differences in the photocycle kinetics
JO  - Biophysical journal
VL  - 91
SN  - 0006-3495
CY  - New York, NY
PB  - Rockefeller Univ. Press
M1  - PreJuSER-52270
SP  - 1441 - 1451
PY  - 2006
N1  - Record converted from VDB: 12.11.2012
AB  - The determination of the intermediate state structures of the bacteriorhodopsin photocycle has lead to an unprecedented level of understanding of the catalytic process exerted by a membrane protein. However, the crystallographic structures of the intermediate states are only relevant if the working cycle is not impaired by the crystal lattice. Therefore, we applied visible and Fourier transform infrared spectroscopy (FTIR) microspectroscopy with microsecond time resolution to compare the photoreaction of a single bacteriorhodopsin crystal to that of bacteriorhodopsin residing in the native purple membrane. The analysis of the FTIR difference spectra of the resolved intermediate states reveals great similarity in structural changes taking place in the crystal and in PM. However, the kinetics of the photocycle are significantly altered in the three-dimensional crystal as compared to PM. Strikingly, the L state decay is accelerated in the crystal, whereas the M decay is delayed. The physical origin of this deviation and the implications for trapping of intermediate states are discussed. As a methodological advance, time-resolved step-scan FTIR spectroscopy on a single protein crystal is demonstrated for the first time which may be used in the future to gauge the functionality of other crystallized proteins with the molecular resolution of vibrational spectroscopy.
KW  - Bacteriorhodopsins: chemistry
KW  - Bacteriorhodopsins: radiation effects
KW  - Bacteriorhodopsins: ultrastructure
KW  - Crystallography: methods
KW  - Dose-Response Relationship, Radiation
KW  - Kinetics
KW  - Light
KW  - Photobiology: methods
KW  - Photochemistry: methods
KW  - Radiation Dosage
KW  - Spectroscopy, Fourier Transform Infrared: methods
KW  - Time Factors
KW  - Bacteriorhodopsins (NLM Chemicals)
KW  - J (WoSType)
LB  - PUB:(DE-HGF)16
C6  - pmid:16731567
C2  - pmc:PMC1518640
UR  - <Go to ISI:>//WOS:000239242000029
DO  - DOI:10.1529/biophysj.106.083345
UR  - https://juser.fz-juelich.de/record/52270
ER  -