1. STRUCTURE OF A KEY LINK IN THE RESPIRATORY CHAIN
by Annette Greiner
(Contact: dcrees@caltech.edu)

Even in bacteria, respiration is not a thing to be taken lightly. Though aerobes and anaerobes do it differently, the protein complexes involved in respiration are homologous across species, even from bacteria to humans. Thus, information about how a microbe "breathes" helps humans understand their own manner of generating energy in cells. Researchers working at the Macromolecular Crystallography Facility (MCF) at the ALS have grasped a big piece of the respiratory jigsaw puzzle by solving the structure of fumarate reductase, or respiratory complex II, from the bacterium E. coli. This protein is similar to succinate dehydrogenase, which catalyzes the oxidation of succinate to fumarate while functioning as complex II in the aerobic bacterial respiratory chain and also as a member of the Krebs cycle in eukaryotes. Fumarate reductase catalyzes the opposite reaction, reducing fumarate to succinate in anaerobic bacterial respiration. The two proteins are so similar that, under certain conditions, one can functionally replace the other.

Read the full story at http://www-als.lbl.gov/als/science/sci_archive/fumarate.html.

Publication about this research: T.M. Iverson, C. Luna-Chavez, G. Cecchini, and D.C. Rees, "Structure of the Escherichia coli Fumarate Reductase Respiratory Complex," Science 284, 1961 (1999).

2. CBS COMES TO ALS TO LEARN ABOUT CLIMATE RESEARCH
(Contact: tacahill@ucdavis.edu)

A crew from the CBS Evening News came to the ALS last month to film a piece about aerosol contaminants from China and their possible effects on the climate of the United States. Tom Cahill (Univ. of California, Davis) was contacted by CBS after presenting a paper on his ALS work at last December's American Geophysical Union meeting. Using x-ray fluorescence techniques at the x-ray microprobe on Beamline 10.3.1, Cahill and his colleagues at UC Davis and San Jose State, working with Scott McHugo of the ALS and Al Thompson of Berkeley Lab's Center for X-Ray Optics, were able to identify the elemental composition of aerosol particles, ranging from light (Si and P) to heavy (As and Se), collected on the West Coast. The concentrations were correlated with aerosol transport episodes observed in Hawaii and suspected of originating from man-made sources in China. The time evolution of the concentrations was obtained with a temporal resolution of 30 minutes. (Resolutions down to 1 minute are possible.) Such detailed information will be necessary before accurate computer modeling of the pollutants' effects and mitigation of Asian sources can begin. The news segment, which culminated a week-long WeatherWatch series on the CBS Evening News, was broadcast on March 31.

3. LAWRENCE POSTDOCTORAL FELLOWSHIPS AVAILABLE

The Lawrence Postdoctoral Fellowship Program is accepting applications through May 15, 2000. The fellowships provide challenging opportunities to conduct research in energy and general sciences, computing, and biosciences. Fellows become integral members of Berkeley Lab research teams, where they gain exposure to current national issues, share and exchange innovative ideas and techniques, and enhance their professional development. One of the primary purposes of the fellowship is to identify, develop, and enhance career opportunities, as well as the overall competitive profile, of members of groups historically underrepresented in their disciplines. More detailed information about eligibility requirements and application procedures is available on line at http://www.lbl.gov/Workplace/WFDO/PostDoc.html.

4. UEC CORNER: NOTES FROM THE USERS' EXECUTIVE COMMITTEE
by Nora Berrah
(Contact: berrah@wmich.edu)

The UEC meeting was held on Tuesday, March 28th. Various agenda items were discussed.

(1) Space allocation close to the ALS building was one issue. The UEC supports the efforts of ALS management to increase the space available to users by constructing a new building. ALS management has asked for UEC input regarding the number of offices, the amount of staging space, and the number of wet labs in the new building before presenting the conceptual design report to the Department of Energy (DOE). If you have suggestions, please send them to Jim Krupnick (JTKrupnick@lbl.gov, 510-486-6480).

(2) Space allocation on the ALS mezzanine was also discussed. The UEC recommends that a formal request process be initiated, where any user requesting space would submit an application listing the amount of space requested and the justification for acquiring the space. These applications would be evaluated by a committee consisting of members from ALS management, the UEC, and other users. The space would then be distributed approximately as follows: about a third of the space will be used to accommodate the ALS Scientific Support Group (beamline scientists) led by Zahid Hussain, another third should be allocated to permanent users (groups with a constant presence and heavy investment in the ALS), and the final third should be set aside for temporary users (faculty on sabbatical, etc). We need two users not associated with the UEC to be part of the space allocation committee. If you are interested in serving on this committee, please contact me (berrah@wmich.edu).

(3) The UEC supported the visit of the chair (Nora Berrah) and vice chair (Harald Ade) to Washington, D.C., on Tuesday, April 11, for an all-day meeting with congressional staffers. The purpose of the visit was to inform Capitol Hill about the importance of synchrotron facilities for basic research. This visit was orchestrated with the user-group chairs of the three other facilities funded by the DOE's Office of Basic Energy Sciences.

(4) We have begun planning the next Users' Meeting, which will be held at the ALS October 16-18, 2000. Please mark your calendars!!! This year we are thinking about having specialized workshops on the second and third days. If you would like to organize a workshop, please contact me (see contact information above). We are considering reserving the first day for a keynote speaker and two or three hot-topic sessions. If you have ideas for types of sessions and speakers we should have, please contact me. Also, if you liked or disliked the student session, let me know. Last year it seemed very successful.

5. WHO'S IN TOWN

Following are some of the experimenters who will be collecting data during the next two weeks at the ALS.

Beamline 1.4.3:
Mary Kauffman (Idaho National Engineering and Environmental Laboratory)
Phil Huie (Stanford Univ.)
Hoi-Ying Holman (Berkeley Lab)
Sherry Zhang and Phil Ross (Berkeley Lab)
Felicia Betancourt and Bob Glaeser (Univ. of California, Berkeley, and Berkeley Lab)
Karl Nieman and Ron Sims (Utah State Univ.)

Beamline 7.3.1.1:
Boris Sinkovic (Univ. of Connecticut)
Z.Q. Qiu (Univ. of California, Berkeley)

Beamline 8.0.1:
Steve Cramer (Univ. of California, Davis)
Jeff Kortright (Berkeley Lab)

Beamline 10.0.1:
Z.X. Shen, S.A. Kellar, and coworkers (Stanford Univ.)
A.J. Yencha (State Univ. of New York-Albany)

Beamline 10.3.1:
Christoph Flink (Berkeley Lab)
Thomas Cahill (Univ. of California, Davis)

6. OPERATIONS UPDATE
(Contact: RMMiller@lbl.gov)

Beam reliability for the last two weeks (March 27 to April 9) was 93% for user shifts. There were no significant outages.

Long-term and weekly operations schedules are available on the Web (http://www- als.lbl.gov/als/accelinfo.html). Requests for special operations use of the "scrubbing" shift should be sent to Bob Miller (RMMiller@lbl.gov, x4738) by 1:00 p.m. Friday. The Accelerator Status Hotline at (510) 486-6766 (ext. 6766 from Lab phones) features a recorded message giving up-to- date information on the operational status of the accelerator.