Iron plays an integral role in many biochemical processes essential for life.
Now, working in part at SSRL's Beam Line 9-2, a team of researchers led by
Martin Lawrence from Montana State University has solved the structure of a
protein critical to the process of importing iron into cells. The results were
published in the May 27, 2008 edition of the Proceedings of the National
Academy of Sciences.
In humans, iron is predominantly found in hemoglobin, the oxygen carrying
component in red blood cells (RBCs). As RBCs mature, they incorporate iron into
hemoglobin. A protein called Steap3 plays a crucial role in this process.
The Steap family includes four proteins involved in various crucial processes.
Malfunction or overexpression of Steap proteins is associated with a range of
diseases, from anemia to prostate cancer. In the current study, the team solved
the structure of the oxidoreductase domain of Steap3 responsible for changing
the oxidation state of iron from Fe3+ to Fe2+. This step
makes it possible for iron to enter the RBC precursor cells where it can be
incorporated into heme, the molecule that gives hemoglobin the capacity for
carrying oxygen.
Understanding the unique structure of the oxidoreductase domain of Steap3 could
lead to more precisely targeted drugs for treating certain disorders, with
fewer side effects. Research is ongoing to understand the overall structures of
the other Steap proteins.
The project was carried out in collaboration with Mark D. Fleming from
Children's Hospital and Harvard Medical School, Boston.
To learn more about this research see the full scientific highlight at:
http://www-ssrl.slac.stanford.edu/research/highlights_archive/steap3.html
2. Science Highlight —
A Different Type of High Temperature Superconductor
(contact: D.H. Lu, dhlu@slac.stanford.edu)
|  |
| Comparison between angle-resolved photoemission spectra and
LDA band structures along two high-symmetry lines.
|
The recent discovery of superconductivity in iron-based layered compounds known
as iron oxypnictides has renewed interest in high-temperature
superconductivity. Now, SLAC and Stanford researchers, using SSRL's angle
resolved photoemission spectrometer at Beam Line 5-4, have furthered the quest
to understand this iron-based compound. In a recent paper published in
Nature,
SSRL scientist Donghui Lu, with colleagues at SSRL and Stanford, reported on
the mechanism behind the superconductivity of a
lanthanum-oxygen-iron-phosphorus (LaOFeP) compound, one of the new iron-based
superconducting materials.
Superconductivity occurs when a material's electrons pair up and electrical
resistance disappears. The precise mechanisms by which this happens are fairly
well understood for conventional superconductors, but remain elusive for
copper-based high temperature superconductors. The new iron-based
superconductors seem to be fundamentally different from both, even though they
operate at high temperatures like the copper oxide superconductors. Lu and
colleagues performed detailed ARPES measurements of the LaOFeP compound, and
the results from these measurements may lead to a deeper understanding of why
the electrons pair up in iron superconductors. That, in turn, could also help
to sort out the essential factors that are important to achieve high
temperature superconductivity.
Although this research suggests that the mechanism behind superconducting
LaOFeP is likely different from the one behind copper oxides, the same may not
hold true for other iron-based oxide compounds. Lu and colleagues are now
conducting experiments at SSRL on an iron-based compound that includes arsenic
instead of phosphorus.
To learn more about this research see the full scientific highlight at:
http://www-ssrl.slac.stanford.edu/research/highlights_archive/LaOFeP.html
3.
Joe Kline to Receive the 2008 Spicer Young Investigator Award
|
 |
Congratulations to R. Joseph Kline who has been chosen to receive the 2008
William E. Spicer Young Investigator Award. The award, honoring one of the
founders of SSRL, recognizes a young investigator who has made important
technical or scientific contributions that benefit the light source community.
The award presentation will take place at the joint LCLS/SSRL Users' Meeting
during the Thursday, October 16 session on young investigator science
highlights.
Kline is a staff scientist at the National Institute of Standards and
Technology (NIST) in Gaithersburg, MD. His thesis work while a graduate student
in Mike McGehee's group at Stanford University and his more recent work as a
NRC-NIST postdoctoral fellow under the supervision of Eric K. Lin, in the
Polymers Division in the Materials Science and Engineering Laboratory, have
been well received by the research community. Specifically, Kline is
recognized for his seminal studies on the effect of molecular weight on the
performance of polymer semiconductor field effect transistors and his expertise
in grazing incidence x-ray diffraction (GIXD), atomic force microscopy, and
organic thin films. According to University of California at Santa Barbara
collaborator Michael Chabinyc, "Joe's previous work continues to generate
interest. He has four publications that have been cited more than 50 times with
increasing numbers of citations each year".
SSRL staff scientist and research collaborator Mike Toney maintains that the
use of SSRL Beam Lines 11-3, 7-2, and 2-1 to conduct x-ray scattering
experiments on polymer thin films was absolutely critical to Kline's thesis
work. McGehee, impressed at Kline's ability to publish a high impact paper
with only five days of beam time, lends some insight: "Joe has an extraordinary
ability to ask the right questions, prepare the right samples, make the right
measurements, and elucidate important structure-property relationships". Also
enthusiastic about Kline's abilities, Lin says, "The impact of his work on the
rapidly growing field of organic electronics has been significant and
highlights the facilities and capabilities at SSRL. He is certainly a rising
star in organic electronics and the application of synchrotron radiation for
materials science".
4.
Annual Users' Meeting October 15-18: Register and Vote
(contact: C. Knotts, knotts@slac.stanford.edu)
Register to participate in the upcoming October 15-17 LCLS/SSRL Users' Meeting
and Workshops. The Users' Meeting will feature presentations on recent
developments and new opportunities to conduct photon science research at the
LCLS and SSRL. SLAC Director Persis Drell will give a keynote presentation on
the future of photon science at SLAC. Several focused workshops (descriptions
below) will be held in conjunction with the meeting.
http://www-conf.slac.stanford.edu/ssrl-lcls/2008/
The polls are now open to fill three open positions for representatives on the
SSRL Users' Organization Executive Committee (SSRL UOEC) including one each in
the areas of materials science and macromolecular crystallography and a
graduate student coming from any of the represented disciplines.
http://www-conf.slac.stanford.edu/ssrl-lcls/2008/SSRLvoteForm.asp
This year there are also a number of slots to fill on the LCLS Users'
Organization Executive Committee (LCLS UOEC) with candidates representing AMO
Science, X-ray Pump-Probe, Coherent X-ray Imaging, and X-ray Photon Correlation
Spectroscopy.
http://www-conf.slac.stanford.edu/ssrl-lcls/2008/LCLSvoteForm.asp
Having full and engaged Users' Organization committees is essential,
particularly during times of growth and change. Please take a few minutes to
cast your ballot between now and October 15. Users' Organization
representatives will be elected by the user community by majority vote, and the
results will be announced on October 16.
5.
LCLS/SSRL Workshops Held in Conjunction with Users' Meeting
| SSRL Workshop: Advanced Topics in
EXAFS Analysis and Applications |
| | October
15, 2008 |
| | Organizers:
R. Sarangi (SSRL) and C. Booth (LBNL) |
|
Extended x-ray absorption fine structure (EXAFS) is a powerful local
structure
determination technique, which has been successfully applied to problems in a
broad range of scientific fields. In recent years, significant research has
been performed towards theoretical development and scientific applications of
EXAFS. The aim of this workshop is twofold:
a) To present recent developments in methods for EXAFS data analysis.
Presentations will cover various aspects of modern analysis tools to address
different analytical approaches, error analysis, alternate fitting methods,
etc.
b) To discuss applications of the EXAFS techniques in different scientific
areas, which include biology, material science, chemistry, geology and physics.
Modern applications of EXAFS, which have been used in combination with other
spectroscopic techniques to answer specific questions in science will be
presented and discussed.
|
| http://www-conf.slac.stanford.edu/ssrl-lcls/2008/program.asp#WedEvent1
|
| SSRL Workshop: Crystallography Made
Easy through Automation
|
| | October 15, 2008
|
| | Organizers:
I. Mathews (SSRL) and E. Snell (HWI) |
|
Recent advances in experimental automation have brought macromolecular
structure determination closer to the non-experts in the field. This workshop
will introduce the participants to what information structural crystallography
can provide, the basics of crystallographic techniques (protein
crystallization, x-ray diffraction data collection, and data analysis) and then
demonstrate how these steps may be simplified by taking advantage of the
automated facilities available at SSRL and the Hauptman Woodward Institute
(HWI). In particular, HWI offers services for high-throughput crystallization
condition screening and optimization and automated facilities at SSRL enable
experimenters to remotely collect x-ray diffraction data for crystal quality
analysis and structure determination using an internet connection at their home
laboratory. SSRL also provides remote access to software and computing
resources necessary for complete structure determination. Participants will get
hands-on experience with some of the automation techniques used at SSRL and
learn how to prepare crystalline samples for remote data collection. Anyone in
the general biology community who is interested in learning about how to make
use of the technique of macromolecular crystallography enabled by automated
technology developments is invited to attend.
|
| http://www-conf.slac.stanford.edu/ssrl-lcls/2008/program.asp#WedEvent2
|
| LCLS Workshop: Application of Coherent X-rays at the
LCLS |
| | October 17,
2008 |
| | Organizers:
A. Robert (LCLS), S. Boutet (LCLS), B. Stephenson (ANL) and
H. Chapman (DESY) |
|
The purpose of this workshop is to bring together world experts on the use of
coherent x-ray beams to study the structure and dynamics of matter. It will
provide a perfect opportunity to discuss the scientific capabilities of the
coherent x-rays that will be produced by LCLS. It will also be a good
opportunity to identify the types of problems that the LCLS will be ideally
suited to answer. Finally, this forum will provide the perfect platform to get
people excited about the LCLS instruments and will be a great starting point to
build the user community for the X-ray Correlation Spectroscopy (XCS) and
Coherent X-ray Imaging (CXI) instruments.
|
| http://www-conf.slac.stanford.edu/ssrl-lcls/2008/program.asp#FriEvent1
|
| LCLS Workshop: Atomic, Molecular & Optical Physics with the
LCLS |
| | October 17,
2008 |
| | Organizers:
J. Bozek (LCLS) and L. Young (ANL) |
|
The purpose of this workshop is to discuss AMO experiments for the LCLS. The
AMO instrument will be the first online at LCLS, and by the time of this
workshop the first round of proposals will have been submitted for
consideration. Scientific opportunities and technical challenges for x-ray FEL
AMO experiments will be discussed.
|
| http://www-conf.slac.stanford.edu/ssrl-lcls/2008/program.asp#FriEvent2 |
| Joint SSRL/LCLS/ALS Workshop: Soft X-ray Beam Line for Material and
Energy Science at the LCLS |
| | October 18,
2008 |
| | Organizers:
W.-S. Lee (SIMES), A. Scherz (SIMES), D. Nordlund (SSRL) and P.
Heimann (LBNL) |
|
The workshop will establish the current status of the LCLS soft x-ray (SXR)
material and energy science consortium and aims for a coherent effort to make
the most compelling science, detailing instrument requirements and
commissioning a success. The participants will learn about the SXR
instrumentation and scientific opportunities. Presentations will cover the
scientific areas and the beam line design for the three main experimental
setups: Coherent Diffraction Imaging, PES/XES/RIXS, and XAS. Each session will
be followed by a directed discussion mainly focusing on instrumentation
including unresolved issues, time line and proposal preparation. Potential
users for the SXR beam line at LCLS are encouraged to give a 5-minute
presentation during the discussion sessions.
|
| http://www-conf.slac.stanford.edu/ssrl-lcls/2008/program.asp#SatEvent1
|
6.
Information Requested for Reports to SSRL Funding Agencies
(contact: C. Knotts, knotts@slac.stanford.edu; L. Dunn,
lisa@slac.stanford.edu)
It is extremely important that users not only inform us whenever work conducted
at SSRL results in a publication, but also acknowledge SSRL and our funding
agencies in each publication. User help is needed to keep current records on
publications including refereed journal papers, conference proceedings, book
chapters and theses, invited lectures and major awards and patents based at
least in part on work conducted at SSRL. This information allows SSRL to
demonstrate scientific achievements and productivity when responding to
requests sent out by the Department of Energy and the National Institutes of
Health.
This information can be submitted anytime via email message to Lisa Dunn or
Cathy Knotts or via the reference submission form at:
http://smb.slac.stanford.edu/forms/reporting/form_publication.shtml
For recent publications lists and the proper acknowledgement statements see:
http://www-ssrl.slac.stanford.edu/publications/
7.
The Fourth Conference on Synchrotron Environmental Science
Organizers: J. Bargar (SSRL) and Peter Nico (LBNL)
|  |
Synchrotron based investigations have made wide-ranging impacts in
environmental science. For example, they have increased our fundamental
understanding of heavy metal bioavailability in contaminated aquifers,
elucidated the mechanisms by which living organisms utilize carbon, sulfur,
chlorine, and metal ions to control the compositions of potable water supplies,
and accelerated the clean-up and closure of radionuclide-contaminated nuclear
legacy sites.
The fourth conference on Synchrotron Environmental Science (SES IV), to be held
in San Francisco, December 11-13, 2008 (immediately prior to the fall 2008
American Geophysical Conference), will highlight the growing role of
synchrotron based studies in environmental science. Presentations from
internationally-renowned speakers will explore emerging scientific frontiers
and current challenges in global environmental problems, including carbon
dioxide sequestration, environmental remediation, climate change, marine
science, and atmospheric science. The conference will also highlight new
synchrotron methods and facility developments in North American. This
conference is supported by DOE Offices of Basic Energy Sciences, Biological and
Environmental Research, and by the US NSF.
Participation by graduate students, post docs, and other prospective
synchrotron facility users is strongly encouraged. One day of hands-on sessions
and introductory-level talks will provide important information, perspectives,
and networking opportunities to these participants. Travel fellowships will be
provided to qualified graduate student and postdoctoral researchers to
encourage their participation.
SES-IV will catalyze new research partnerships and opportunities in earth,
energy, and environmental sciences. All who are interested are invited to
participate and to visit the conference web site at:
http://esd.lbl.gov/sesIV08/
8.
Beam Line Update
The Upgraded BL4-2 Awaits the Return of Structural Molecular Biology
Users
(contact: H. Tsuruta, tsuruta@slac.stanford.edu)
The SMB bioSAXS/D station Beam Line 4-2 received its SPEAR3 optics upgrade
earlier this year and the new station was successfully commissioned during the
FY08 user run. We anticipate hosting the full range of experimental activities
on BL4-2 beginning in December. The 20-pole wiggler end station, now located in
Building 130, employs a Rh-coated toroidal focusing mirror and a cryogenically
cooled double crystal monochromator with interchangeable pairs of Si(111) and
multilayer crystals. A 7.5-m long new experimental hutch was built to
accommodate longer sample-to-detector distances. The beam flux using the
Si(111) crystals with the standard focused beam size of 0.2mmx0.8mm FWHM is 4
times higher than previous years due to use of the full wiggler field, which
has been enabled by the upgrade, shortening exposure time of 10-15s to just a
few seconds for typical protein solution scattering studies. The use of the
multilayer monochromator further increases the beam flux by a factor of 20 to
allow fast time-resolved studies. The 500-mA operation of SPEAR3 will further
enhance the beam flux. The higher mirror cut-off energy of 17 keV allows
anomalous scattering studies at biologically relevant absorption edges that
were previously not accessible. The in-hutch instrumentation for
non-crystalline x-ray scattering and diffraction studies on biological systems
has also received an extensive array of hardware and software upgrades. The
segmented beam flight path has been rebuilt to provide the shortest and longest
sample-to-detector distances of 0.25 and 3.5m, respectively. A
computer-controlled distance change mechanism covers the Q range of 0.003-3.7
Å-1 with seven discrete distances. Another significant enhancement
is the acquisition of a Rayonix MX225-HE detector, which has been delivered and
was characterized during beam line commissioning. The substantially improved
photon sensitivity and electronic stability as compared to the previous
MarCCD165 detector are highly advantageous when working with low concentration
samples. Its larger active area improves accessibility to higher scattering
angles at all distances. In addition to a number of other hardware
improvements, we have been updating the BL4-2 Blu-ICE/DCS software to control
new hardware as well as to provide improved experiment control, in particular
for high throughput solution scattering studies. We further anticipate the
availability of a new time-resolved x-ray detector and significantly improved
sample handling devices during the FY09 run.
New X-ray Microscopy Facility for Bioimaging on BL6-2
(contact J. Hayter, jandrews@slac.stanford.edu)
An x-ray microscopy facility for bioimaging, based on an Xradia nano-XCT
transmission x-ray microscope (TXM), has been developed at the BL6-2 wiggler
beam line at SSRL (http://www-ssrl.slac.stanford.edu/beamlines/bl6-2/txm/). The
instrument has been designed to operate in the photon energy range from 5-14
keV in absorption contrast, and at 8 keV (and soon 5 keV) in Zernike phase
contrast, with 40 nm resolution. The TXM field of view is 14x14
mm2 field of
view, and larger mosaics of up to 20x20 individual exposures can be used to
survey large sample areas. The sample stage rotates for 3D tomography. The
microscope has been used to image biological samples such as bones, teeth, and
yeast cells, environmental samples such as plants which have absorbed heavy
metals, and nanomaterials, computer chips and meteorite particles. A
fluorescence detector is being added to the system thus allowing elemental
mapping of a site of interest. If you are interested in using the microscope,
please contact Joy Andrews Hayter (jandrews@slac.stanford.edu) or Piero
Pianetta (pianetta@stanford.edu). We will be glad to help you incorporate this
into your new beam time proposal.
New Scanning Transmission X-ray Microscope (STXM) Facility
(contact: H. Ohldag,
hohldag@slac.stanford.edu)
A new Scanning Transmission X-ray Microscope (STXM) beam line is being
installed, with plans for user operations later in 2009. The new STXM BL13-1
will allow the study of magnetic phenomena with a spatial resolution of 40 nm
or less using soft x-rays in the energy range between 250 and 1000 eV. In such
a microscope, x-rays are focused down to a spot of 40 nm or less onto the
sample using a Fresnel Zone Plate. The sample is then scanned perpendicular to
the incoming beam, while the transmitted intensity is detected behind the
sample using a photodiode or a photomultiplier. Samples for such a microscope
are typically grown on substrates that are transparent to soft x-rays, like
membranes made of silicone nitrides. The microscope will be able to operate in
an ultra high vacuum environment (<=10-9 mbar) and in a variable
temperature range (25 - 450 K), thus allowing for studying field and
temperature dependent magnetic phenomena. It will also be equipped with
electrical feedthroughs to apply electric currents and pulses to the sample.
http://www-ssrl.slac.stanford.edu/beamlines/bl13-1/
9.
User Research Administration Update
(contact: C. Knotts, knotts@slac.stanford.edu)
As mentioned, in part, above, we have been busy over the last year upgrading
and building new beam lines for our users. Beginning in December, BL13-2
(http://www-ssrl.slac.stanford.edu/beamlines/bl13-2/) will be
available for PES and NEXAFS experiments, and Coherent Scattering experiments
can be done on BL13-3 (http://www-ssrl.slac.stanford.edu/beamlines/bl13-3/). We
also anticipate that XAS experiments will resume on BL4-1 and BL4-3 beginning
in January.
If you are interested in exploring our latest capabilities or planning new
experiments utilizing SSRL's beam lines, please submit an X-ray/VUV proposal by
November 1 or macromolecular crystallography proposal by December 1.
http://www-ssrl.slac.stanford.edu/userresources/proposals.html
__________________________________________________________________________
SSRL Headlines is published electronically monthly to inform SSRL users,
sponsors and other interested people about happenings at SSRL. SSRL is a
national synchrotron user facility operated by Stanford University for the
U.S. Department of Energy Office of Basic Energy
Sciences. Additional support for
the structural biology program is provided by
the DOE
Office of Biological and Environmental Research, the NIH
National Center for Research Resources and the NIH Institute for General Medical
Sciences. Additional information about
SSRL and its operation and schedules is available from the SSRL WWW
site.
__________________________________________________________________________
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