Room temperature femtosecond X-ray diffraction of photosystem II microcrystals.
Most of the dioxygen on earth is generated by the oxidation of water by photosystem II (PS II) using light from the sun. This light-driven, four-photon reaction is catalyzed by the Mn(4)CaO(5) cluster located at the lumenal side of PS II. Various X-ray studies have been carried out at cryogenic temperatures to understand the intermediate steps involved in the water oxidation mechanism. However, the necessity for collecting data at room temperature, especially for studying the transient steps during the O-O bond formation, requires the development of new methodologies. In this paper we report room temperature X-ray diffraction data of PS II microcrystals obtained using ultrashort (< 50 fs) 9 keV X-ray pulses from a hard X-ray free electron laser, namely the Linac Coherent Light Source. The results presented here demonstrate that the "probe before destroy" approach using an X-ray free electron laser works even for the highly-sensitive Mn(4)CaO(5) cluster in PS II at room temperature. We show that these data are comparable to those obtained in synchrotron radiation studies as seen by the similarities in the overall structure of the helices, the protein subunits and the location of the various cofactors. This work is, therefore, an important step toward future studies for resolving the structure of the Mn(4)CaO(5) cluster without any damage at room temperature, and of the reaction intermediates of PS II during O-O bond formation.
Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
Jan
J
Kern
Roberto
R
Alonso-Mori
Julia
J
Hellmich
Rosalie
R
Tran
Johan
J
Hattne
Hartawan
H
Laksmono
Carina
C
Glöckner
Nathaniel
N
Echols
Raymond G
RG
Sierra
Jonas
J
Sellberg
Benedikt
B
Lassalle-Kaiser
Richard J
RJ
Gildea
Pieter
P
Glatzel
Ralf W
RW
Grosse-Kunstleve
Matthew J
MJ
Latimer
Trevor A
TA
McQueen
Dörte
D
DiFiore
Alan R
AR
Fry
Marc
M
Messerschmidt
Alan
A
Miahnahri
Donald W
DW
Schafer
M Marvin
MM
Seibert
Dimosthenis
D
Sokaras
Tsu-Chien
TC
Weng
Petrus H
PH
Zwart
William E
WE
White
Paul D
PD
Adams
Michael J
MJ
Bogan
Sébastien
S
Boutet
Garth J
GJ
Williams
Johannes
J
Messinger
Nicholas K
NK
Sauter
Athina
A
Zouni
Uwe
U
Bergmann
Junko
J
Yano
Vittal K
VK
Yachandra
D002384:Catalysis; D003460:Crystallization; D018360:Crystallography, X-Ray / Q000379:methods*; D008958:Models, Molecular; D045332:Photosystem II Protein Complex / Q000737:chemistry*
D045332:Photosystem II Protein Complex