Dr. Denis Raoux, Director
General of the new French Synchrotron facility SOLEIL visiting the
laboratory. He gave a seminar on "The Status of SOLEIL - the French
Synchrotron project"
10/12/03
Synchrotron Sheds Light on Bacteria’s
Solar Cell
Researchers based at the University of Glasgow, using X-ray data
collected at the Synchrotron Radiation Source (SRS) at CCLRC Daresbury Laboratory,
have made a major advance in our understanding of the process by which sunlight
is converted to food energy, without which life on earth could not exist. The
work is published this week (12 December 2003) in the journal Science.
Green plants convert the sun’s energy to a usable form
in a process called photosynthesis, which ultimately gives us all the oxygen
and food we need to survive. Photosynthetic bacteria have evolved to do all
this efficiently in a single cell, so they make good model systems. The Glasgow
team, led by Professors Richard Cogdell and Neil Isaacs, worked out the structure
of the LH1 light-absorbing complex and Reaction Centre that lies at the heart
of photosynthesis in the purple bacterium Rhodopseudomonas palustris.
They first isolated and crystallised the intact protein complex
from the bacterial cell membrane, then recorded its X-ray diffraction pattern
using X-rays generated at the Daresbury synchrotron.‘The highly focused
and intense X-ray beam provided at Daresbury was essential for this data collection’,
commented Professor Isaacs.
The X-ray data helped to solve a long-standing mystery about
the structure of the LH1-RC. Solar energy absorbed by the light harvesting
complex is used by the Reaction Centre to power the transfer of electrons across
the cell membrane, using a shuttle molecule to carry the electrons. Researchers
have been puzzled about how this shuttle molecule gets in and out of the Reaction
Centre, which is surrounded by the ring of protein molecules that makes up
the LH1. The structure shows that the LH1 ring has a molecular ‘gate’ to
enable the shuttle molecule to move freely.
Since 1984 the structures of only 25 membrane proteins have been
worked out, compared with around 15,000 soluble ones. ‘Membrane proteins
are notoriously difficult to crystallise in the first instance,’ explained
Miroslav Papiz, Head of the Biology and Medicine College at Daresbury, ‘and
when crystals are obtained they nearly always diffract very weakly. This is
why such an intense source of X-rays is needed to study them.’
This work is the third major breakthrough in this fundamental
area of biological research to be based on X-ray crystallographic data collected
at the SRS. In 1995 the teams of Richard Cogdell and Neil Isaacs at Glasgow,
in collaboration with Miroslav Papiz and the Daresbury team, elucidated the
structure of another key component of the light-harvesting machinery, the LH2
complex, from the purple bacterium Rhodopseudomonas acidophila. The LH2 complex
funnels energy into the LH1 complex. This year the resolution of this structure
has been further improved, helping to reveal more details about energy transfer
within it.
NOTES
X-ray diffraction techniques allow researchers to study the
precise structure of biological molecules such as proteins, as the first
essential step in understanding how they work. The proteins are isolated,
crystallised and placed in the path of an intense x-ray beam. The pattern
produced by X-ray scattering from the atoms can be converted mathematically
to a map of their exact position relative to each other.
Richard Cogdell is in the Faculty of Biomedical and Life Sciences,
Division of Biochemistry and Molecular Biology, University of Glasgow, Glasgow
G12 8QQ, UK; Neil Isaacs is in the Department of Chemistry, also at the University
of Glasgow. Their paper, by Aleksander W. Roszak et al., is published in
the 12 December 2003 issue of Science.
There are more than 70 components in the purple bacterial photosynthetic
system, comprising proteins, light-absorbing pigments and carotenoid molecules.
The Sun’s energy is trapped as an excited energy wave in a two-stage
light harvesting system made of proteins and pigment molecules organised
into circular assemblies (a peripheral ring, LH2, and a larger inner ring,
LH1, which closely surrounds the reaction centre, RC). Within the RC solar
energy is used up in transferring electrons to a molecule called ubiquinone.
Ubiquinone shuttles between the RC and a pigment complex in the bacterial
cell membrane, delivering electrons and setting up an imbalance of electrical
charge there. This imbalance in turn drives the ‘energy enzyme’,
ATP synthase, to bring about the conversion of ADP (adenosine diphosphate)
to ATP (adenosine triphosphate), the energy-rich molecule used as ‘currency’ in
biological processes. The Glasgow team’s success means that the structures
of all four major elements of this molecular energy generator have now been
worked out.
For more information contact Tony Buckley (CCLRC Daresbury Laboratory
Press Officer)
tel: 01925 603272 fax: 01925 603195 e-mail: a.g.buckley@cclrc.ac.uk
08/10/03
ROADWORKS AROUND THE SITE - current
roadwork information >>
Carriageway works on Keckwick Lane will begin on Monday
13 October and will take approximately 19 weeks.Work will be carried
out in several phases and each phase will entail changes to the way the DL
site is accessed.
Phase One begins on Monday 13 October for a period of approximately 4 weeks.
The western side of Keckwick Lane will be closed to traffic from Keckwick Lane
bridge to just above Gate B (mid car park). A three way traffic light system
will be in place during this period.
Please see the notice and plan for in depth information, check back regularly
with the User
Liaison Office for updates.
Progress and timescales are dependant on the weather & other
factors.
02/09/03
Things are hotting up on the high-pressure front.
The work of CCLRC Daresbury Laboratory's Dr Simon Clark has been recognised
by his appointment as an Honorary Professor in the department of Earth Sciences,
Manchester University.
Simon has been leading the development of systems for high-pressure research
at the SRS for some time and applying them to solving problems not only in
the Earth Sciences but also in Chemistry and Physics. These systems allow researchers
to study materials held at pressure and temperatures similar to those at the
centre of the Earth. Currently on attachment in Berkeley, California, Simon
is developing laser heated high-pressure systems that will allow the study
of materials at pressure and temperatures similar to those found in brown dwarfs.
05/08/03
College of Biology and Medicine website
launched>>
24/06/03
Invitation to Submit expressions of Interest under the
CCLRC Facility Development Project Grant Scheme. First call under the new Facility Development Project Grant Scheme which is
targeted at the continued development of the CCLRC large research facilities..
The total funding available via this scheme, for this call, will be up to £3.8M. ...more>>
17/07/03
The "Motor Neurone Disease: Function and Mis-Function
of Proteins" meeting, organised jointly between CCLRC and the MND
Association, was held at Daresbury Laboratory on the 7th July 2003.
Read the 'Thumbprint' magazine
article (pdf) It's good to talk! featuring
this meeting.
Professor Mike Chesters has been appointed as
Director, Synchrotron Science and will take up this position, based at Daresbury,
on 1 June 2003.
Mike joins CCLRC from Nottingham University where he was Professor and Head
of Physical Chemistry.
02/04/03
£11.5 millon for World-Leading Project at Daresbury Laboratory
Ministers give go-ahead for the next development stage
of 4GLS in Cheshire
The building of the world-leading 4GLS (4th generation light
source) has come one step closer with the announcement today of £11.5
million for an exploratory phase of the project. This phase involves a 3-year
study to establish the technical know-how needed to build this innovative scientific
research facility, includingthe construction of a prototype test facility.
4GLS is a proposed major research facility. If constructed, it
would produce very short pulses of light, over a million, million, million
times brighter than a household light bulb. Its peak power would be roughly
equivalent to that needed to light every home in London. It would allow researchers
to study molecules working in real time, follow chemical reactions as they
happen, look at potential drug molecules as they interact with cells and examine
the spin of electrons. The research carried out on 4GLS would help develop
the next generation of computer memories, pharmaceuticals and catalysts. ...more...
£25.7million for Daresbury's Science Park
The NWDA are pleased to announce funding of £25.7
million in order to develop Daresbury’s Science Park,securing its future
as a centre of excellence for scientific research and development. ...more...
17/01/03
NEW YEAR HONOURS 2003
Professor Louise Johnson FRS, David Phillips
Professor of Molecular Biophysics, University of Oxford has been awarded Dames
Commander of the Order of the British Empire for services to Biophysical Science.
...more...
14/01/03
Resignation of John Helliwell
Professor John Helliwell has decided to step down from the position
of Director, Synchrotron Radiation (SR) at the CCLRC - a post he has held since
January 2002, on secondment from the University of Manchester. more
here...
