what can we learn with xfel radiation?

What can we learn with XFEL radiation?

Johan Hattne February 2013

What can we learn with XFEL radiation | February 2013

Unlocking the mysteries of photosynthesis: photosystem II (PS II)

•  Critical for sustaining aerobic life –  Found in green plants, algae,

and cyanobacteria •  Powered by photons absorbed

by Chl around an Mn-rich catalytic center

•  Protein residues provide pathways for electrons, substrates, and products

•  Artificial photosynthesis using earth-abundant elements? Kok et al. (1970) Photochem

Photobiol 11, 457–475


How does water oxidation work?

Mn

Ca O

OMn

O

O

Mn

O

Cl

O

Mn

HN NH2

ND170W

HH

O HH

O OHO

H

H

CP43-R357

A344

Mn

Ca O

OMn

O

O

Mn

OCl

Mn

HN N

ND170W

HH

O H

H *O OH

H

CP43-R357

A344

H

H

Mn

Ca O

OMn

O

O

Mn

OHCl

Mn

HN NH2

H2ND170W

O H

H OH

H

CP43-R357

A344Mn

Ca O

OMn

O

O

Mn

HOCl

Mn

D170W

O HHO O

H

A344

HH

Mn

Ca O

OMn

O

O

Mn

HOCl

Mn

HN NH2

NH2

D170W

O HHO O

H

CP43-R357

A344

HH

e-

e-

S1

S2

S3

S4

S0

H+, e-H+, e-

H2O

H+, e-

H2O

Sproviero et al. (2008) Chem Rev 252, 395

Mn3 OOHO

O

O Mn2

Mn1Mn4

W

WW

Ca O Mn3 OOW

O

O Mn2

Mn1Mn4

W

WO

Ca O

Mn3 OOW

O

O Mn2

Mn1Mn4

W

HOW

Ca OMn3 OOHO

O

O Mn2

Mn1Mn4

W

WO

Ca O

(a) (b)

(c) (d)

Yamanaka et al. (2011) Chem Phys Lett 511, 138

McEvoy & Brudvig (2006) Chem Rev 106, 4455 Siegbahn (2009)

Acc Chem Res 42, 1871


•  Structural dynamics –  Protein side-chain motions –  Quinone sites –  Geometry of the Mn4CaO5 cluster

•  Chemistry at the Mn4CaO5 site –  Charge density changes of Mn –  Ligand environment changes

•  Time-resolved coupling between atomic motion and electronic structure

Towards an understanding of PS II


X-ray diffraction

•  Radiation damage –  Measurement problem of PS II:

OEC collapses due to radiation damage

•  Dehydrated or cryo-cooled sample does not turn over •  S4 is kinetically unstable and cannot be cryo-trapped •  Interesting biology is dynamic


SFX—serial femtosecond crystallography

•  Experiment run at room temperature

•  Radiation damage does not accumulate •  No time for dehydration •  Can follow reaction dynamics!

X-ray probe

Sample injector

Laser pump

Diffraction detector


SFX: collect-before-destroy

Neutze et al. (2000) Nature 406, 752–757

•  Hydrolase from Coccidioides immitis –  Globular shape –  392 aa in one chain –  0.3 nm water layer

•  Total pulse –  Flux 1012 X-ray photons –  FWHM 20 fs


Crystallography results

Kern et al. (2012) PNAS 109, 9721–9726


SFX: atomic resolution

•  Boutet et al. (2012): lysozyme diffracting to 1.9 Å resolution

•  Unpublished: thermolysin diffracting to 1.4 Å resolution

Lysozyme (1.9 Å): Boutet et al. (2012) Science 337, 362–364


X-ray spectroscopy

•  Study electronic structure of Mn-cluster –  Follow reaction dynamics with pump-probe

•  X-ray absorption –  Study O–O bond formation

•  X-ray emission –  Can be done simultaneously with X-ray diffraction


Simultaneous XRD and XES

X-ray probe

Sample injector

Laser pump

Diffraction detector

Emission detector

Spectrometer

•  Spectrometer focuses emisson signal on PSD •  Simultaneous collection of X-ray diffraction and X-ray

emission –  Record atomic and electronic structure from the same sample


XES of Mn model compounds

Alonso-Mori et al. (2012) PNAS 109, 19103–19107

•  Intact electronic structure of redox-active transition metal compounds in different oxidation states

–  Paves the way for studying PS II oxygen-evolving complex


Simultaneous XRD and XES

•  XRD and XES provide complementary information –  XRD gives geometric structure of overall protein –  XES gives local chemistry of active metal sites

•  Complementary information is useful for data processing –  Crystal hits determined from XRD –  Can infer atomic distances from XES, even when diffracting

resolution too low


What do we still have to learn with XFEL radiation?

•  Stable sample delivery –  Undamaged, single crystals –  High hit rate

•  Big data > small data –  Metadata-intensive operations become prohibitively expensive –  Expect 1.1 GB/s in the near future (SATA rev. 3: 0.6 GB/s)

•  How to write distributed file systems that work –  Open-source development model inefficient –  Small academic user-base not commercially attractive

•  How to make hardware that works –  Robust RAID controllers, network adaptors, etc.


Acknowledgements •  Paul Adams &

Nicholas Sauter –  Aaron Brewster –  Richard Gildea –  Ralf Grosse-Kunstleve –  Nathaniel Echols –  Peter Zwart

•  Alexei Erko & Alexander Föhlisch

–  Rolf Mitzner –  Wilson Quevedo –  Jens Rehanek –  Henning Schroeder –  Christian Weniger –  Philippe Wernet

•  Johannes Messinger

–  Sergey Koroidov

•  SLAC –  Roberto Alonso-Mori –  Uwe Bergmann –  Mike Bogan –  Sébastien Boutet –  Mikhail Dubrovin –  Hartawan Laksmono –  Marc Messerschmidt –  Raymond Sierra –  Ingrid Ofte –  Garth Williams

•  Vitttal Yachandra & Junko Yano

–  Sheraz Gul –  Guangye Han –  Jan Kern –  Benedikt Lasalle-Kaiser –  Henning Schröder –  Rosalie Tran

•  Athina Zouni

–  Julia Hellmich –  Carina Glöckner

what can we learn with xfel radiation?

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