Correlating ultrafast function with structure in single crystals of the photosynthetic reaction center.
Femtosecond transient absorbance spectroscopy was applied to the study of primary electron transfer in single reaction center crystals from Rhodobacter sphaeroides. Polarized transient absorption spectra of individual crystals are shown to correlate with polarized ground-state absorption spectra and to track cofactor transition moment directions calculated from the crystallographic structure. Electron transfer from the bacteriochlorophyll dimer to the bacteriopheophytin acceptor was found to be multiphasic in crystals and approximately 2-fold slower than in solution. This work demonstrates the ability to resolve ultrafast photosynthetic function in single crystals and allows ultrafast function to be directly correlated with structure.
Chemical Sciences and Engineering Division, Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439-4831, USA.
Libai
L
Huang
Gary P
GP
Wiederrecht
Lisa M
LM
Utschig
Sandra L
SL
Schlesselman
Christina
C
Xydis
Philip D
PD
Laible
Deborah K
DK
Hanson
David M
DM
Tiede
D003460:Crystallization; D018360:Crystallography, X-Ray; D004579:Electron Transport; D007700:Kinetics; D008958:Models, Molecular; D046912:Multiprotein Complexes / Q000737:chemistry; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry* / Q000378:metabolism*; D012242:Rhodobacter sphaeroides / Q000737:chemistry / Q000378:metabolism; D012996:Solutions; D013053:Spectrophotometry; D013816:Thermodynamics
D046912:Multiprotein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins; D012996:Solutions