High Brilliance SAXS on Synchrotrons

Transcription

1 High Brilliance SAXS on Synchrotrons Manfred Roessle Luebeck University of Applied Science Lab of X-ray Engineering

2 X-ray generation Synchrotron Sources Shanghai Synchrotron Radiation Facility China Deutsches Elektronen Synchrotron Hamburg Germany European Synchrotron Radiation Facility Grenoble France Spring8, Himeij, Japan Advances Photon Source Chicago USA

3 X-ray generation Synchrotron Dipole bending magnet (APS)

4 X-ray generation Synchrotron Electrons are deflected in the magnetic field of a dipole magnet by the Lorentz-force. X-ray Bremsstrahlung e - E i h = E i - E f Accelerated charges are producing electromagnetic radiation! e - E f Synchrotron radiation emitted by a dipole magnet

5 X-ray generation Synchrotron Undulator Most powerful insertion device! A stack of magnetic dipoles generate a high flux of photons in a very small source size. The specific arrangement of the dipoles with distance d=n* produces a discrete spectrum with coherent properties. High brilliance X-ray beam at ESRF s ID09!

6 X-ray generation Synchrotron radiation The opening angle of synchrotron radiation from relativistic particles is: 1 E E 0 m c m0c E 2 1 v c 2

7 X-ray generation Synchrotron radiation PETRA III Increase of the beam brilliance from X-ray tubes to third generation sychrotron sources to free electron lasers (forth generation)

8 High Brilliance Definition brilliance = photons second mrad 2 mm 2 0.1% BW Brilliance describes: 1. The number of photons per second 2. The number of photons per area (mm 2 ) 3. How the beam is spread out (mrad 2 ), or how the beam opens 4. How monochromatic the beam is (0.1% BW) Bandwidth (BW) Center wavelength

9 X-ray Beamlines EMBL Hamburg Spilotros

10 X-ray Beamlines EMBL Hamburg Beamstop with diode for measurement of transmitted beam Blocked area on the detector Sample cell Sample detector distance (1-5 m)

11 X-ray Beamlines EMBL Hamburg Because of the special arrangement of the beamline components for recording small scattering angles a very parallel X-ray beam is needed. Otherwise the scattering signal will be spread and smeared all over the detector! Towards the detector Incoming X-rays

12 X-ray Beamlines EMBL Hamburg PILATUS 2M P12 Beam size and divergence at modern SAXS Synchrotron beamlines 205*64 µm 2 High brilliance beamlines for structural biology High flux of photons in very small focal X-ray beam spots! Downscaling of the sample container to fit the beam sizes. 40*15 rad 2

13 Motivation for high brilliance beams Low sample volume 1000 Volume in nanoliter Volume in nanoliter ,5 1 Side lenght 6 in mm The volume scales with L 3 A cube of 0.2 mm side length has a volume of 8 nanoliter! A sphere of 0.2 mm diameter has 4 nanoliter! ,05 0,1 0,15 0,2 0,25 Side lenght in mm

14 Radiation damage flow fixed Courtesy Melissa Gräwert

15 Radiation damage flow fixed Courtesy Melissa Gräwert

16 Radiation damage flow fixed Courtesy Melissa Gräwert

17 Radiation damage flow fixed Courtesy Melissa Gräwert

18 High Throughput Screening SAXS Protein under different conditions Liquid handling robot for protein solution samples. Automated washing, rinsing and filling. Total sample volume 15 µl. Complete filling cycle 20 sec. About 40 minutes are needed to screen a standard well plate with 96 samples, and a volume of 1.5 ml!

19 High Throughput Screening SAXS Protein under different conditions Screening of the crystallization conditions of a protein The protein crystallized as dimer, trimer or tetramer in the unit cell Influence of the crystallization buffer on the oligomeric state of the protein Protein under 96 different conditions screened in a well plate with corresponding buffers Intensity [a.u.] q [nm -1 ]

20 High Throughput Screening SAXS Protein under different conditions Analysis of about 400 scattering functions using the automated SAXS pipeline of EMBL Hamburg! Automated results on radius of gyration and molecular weight!

21 High Throughput Screening SAXS Protein under different conditions Results on the distribution of Rg upon different conditions. count tetramer monomer Rg [Å]

22 High Throughput Screening SAXS

23 High Screening SAXS Size Exclusion Approach Courtesy Melissa Gräwert Online sample preparation and SAXS data recording in a thin flow cell. Reduction of radiation damage and check for sample mono dispersity.

24 High Screening SAXS Size Exclusion Approach Results on the SAXS standard protein BSA showed clearly the dimeric and monomeric form of the protein. The pure monomeric phase is used for model building.

25 Time resolved Experiments Access to structural dynamics Eadweard Muybridge (1840 to 1904) British photographer and pioneer in motion pictures

26 Time resolved Experiments Access to structural dynamics

27 Time resolved Experiments Access to structural dynamics

28 Time resolved SAXS The Chaperonin folding machinery Chaperones of the GroE family are part of the heat shock response of a bacterial cell. It consists of the large GroEL cylindrical protein and a small GroES lid. Highly symmetrical particles: 2 x 7 subunits GroEL 1 x 7 subunits GroES The refolding is a multistep ATP driven process and allosteric regulated. Nice system for small angle scattering!

29 Reactand A Reactand B Lab for X-ray Engineering Time resolved SAXS Investigation of Structural Kinetics Example: Reaction kinetics of an ATP driven two component protein system. Classical stopped-flow experiment. mixer Typical mixing time in the range of several ms Suitable for the sub-second time range 50µl to 80µl total volume on a third generation synchrotron radiation source such as the ESRF s ID02 about 5 to 10 repetitions necessary quartz capillary M. Roessle et. al. J.Appl. Cryst. Repetitive measurements High sample consumption Need of a suitable detector system Time resolution ~ 10ms

30 radius of gyration [Å] Lab for X-ray Engineering Time resolved SAXS The Chaperonin folding machinery (GroEL+ GroES) + ADP (1mM) (GroEL + GroES) + ATP (0.1mM) GroEL + Buffer (Referenz) 64 Modulation of the radius of gyration upon the binding of nucleotides. The binding of the nucleotides seems to be highly cooperative time [s] 30 40

31 Time resolved SAXS Fast mixing in continuous flow fast mixing times ~10µs to ~100µs continuous flow method but small sample consumption! micromachining or lithographic technology Akyama, PNAS 2002 L. Pollack PNAS 1999 Akiyama et al. PNAS 2002

32 Online sample preparation Solution mixing and delivery Courtesy: Daniel Mark HSG-INIT/IMTEK

33 Online sample preparation SAXS-CD 7 independent screeing series 12 screeing points Metering and mixing on the chip Inlets for protein, buffer and screening solution Sample vail diameter 200 µm Single volume 3 nl Total volume < 0.5 µl (specification) Collaboration with a German competence center for microsystem technique Imtek Freiburg. Institut für Mikrosystemtechnik Universität Freiburg

34 Online sample preparation Microfluidic Lab-on-a-chip capillary electrophoresis Diameter of the channels m Separation by electro osmotic forces Adaptable on a micro lab-on-a-chip Good resolution power Faster than classical separation methods Sharp separation border, less dilution Pressure driven Voltage driven Standard technique for protein separation, widely used 2dim separations possible e.g. in combination with gel filtration

35 Online sample preparation Micro protein purification Overview Printhead front Substrate carrier HV Direct fluidic preparation on the beamline! Printhead back Signal detection No microfluidic chip needed, electrophoresis in the online prepared gel line.

36 Online sample preparation Micro reactors ESRF microfocus beamline ID 13 Sample environment depends on scientific question e.g. silk fiber maturation under shear forces A. Martel et. al. Biomicrofluidics 2008

37 Online sample preparation Micro reactors for fast structural kinetics Mixing of the droplets by collision is very fast t mix ~ 10µs Following the reaction by scanning the flow after the mixing with the X-ray microbeam. Example: droplet volume: 65pl droplet frequency: 1000Hz exposure time : 10s time points : µl Volume Reagent A t 0 t reag Reagent B High brilliance X-ray beam

38 Synchrotron radiation microdiffraction of ballistic molten wax microdrops R. Graceffa, M. Burghammer, R. J. Davies, and C. Riekel; REVIEW OF SCIENTIFIC INSTRUMENTS 79, (2008)

39 Time resolved SAXS/WAXS Access to structural dynamics Kinetics: Every individual is behaving individual. Dynamics: All individuals are behaving in the same way. Estimation on the reaction velocity and the order of the reaction Analysis on the reaction intermediates and intermediate structures.

40 Time resolved SAXS/WAXS Access to structural dynamics Laser induced conformational change of hemoglobin TR SAXS/WAXS in the sub µs time scale M. Cammarata et. al Nat. Meth

41 Time resolved SAXS/WAXS Structural Dynamics Caged ATP Possible reaction triggering by flash photolysis of so called caged components such as caged nucleotides (caged ADP, caged ATP etc.). A photosensitive protection group inhibits the normal hydrolysis process of the nucleotide, but the protection group can be cleaved from the nucleotide by a strong, fast light flash. Photosensitive protection group Reactive ATP

42 Time resolved SAXS/WAXS In Future: Structural Dynamics

43 Time resolved SAXS/WAXS In Future: Structural Dynamics

44 PETRA III BioSAXS Operation mode and flux Mode Size (H), mm Div. (H), μrad Size (V), mm Div. (V), μrad Flux, ph/s DCM 4 kev x DCM 8 kev x DCM 12 kev x DCM 20 kev x MLM 7.9 kev x Pink 7.9 kev x 10 15

45 PETRA III BioSAXS Multilayer monochromator Increased bandwidth (BW) of a high flux multilayer monochromator. The larger bandwidth ~ 1% increases the intensity by a factor of 100! High heat load on the optical elements!!

46 Coherent SAXS On the way to single particle structural biology Classical SAXS approach: averaging over whole ensemble of particles averaged in time This leads to isotropic scattering data with 1-dimensional information Coherent X-ray solution scattering approach: Scattering of a few molecules (e.g. gas phase or cryo fixed) Ultra short pulse duration Speckled coherent scattering pattern 2-dimensional information Z. Kam Macromolecules 1977; Y. Nishino Biology with FEL s 2011

47 Acknowledgment PureSAXS and SAXS CD project University of Freiburg Prof. Zengerle Frank Schwemmer Lutz Riegger Daniel Mark Norbert Endlich Stefan Kloppotek Atilla Narin EMBL Hamburg SAXS group Dmitri Svergun Melissa Gräwert Clement Blanchet