1. ENZYME STRUCTURE PROVIDES CLUES TO DNA TRANSCRIPTION DETAILS
by Lori Tamura
(Contacts: kornberg@stanford.edu)

Before a cell can begin to divide or differentiate, the genetic information within the cell's DNA must be copied, or "transcribed," onto complementary strands of RNA. RNA polymerase II (pol II) is an enzyme that, by itself, can unwind the DNA double helix, synthesize RNA, and proofread the result. When combined with other molecules that regulate and control the transcription process, pol II is the key to successful interpretion of an organism's genetic code. However, the size, complexity, scarcity, and fragility of pol II complexes have made analysis of these macromolecules by x-ray crystallography a formidable challenge. A team of structural biologists has met this challenge using data obtained from both the Stanford Synchrotron Radiation Laboratory and the Macromolecular Crystallography Facility at the ALS. The resultant high-resolution model of a 10-subunit pol II complex suggests roles for each of the subunits and will allow researchers to begin unraveling the intricacies of DNA transcription and its role in gene expression.

Read the full story at http://www-als.lbl.gov/als/science/sci_archive/polymerase2.html.

Publication about this research: P. Cramer, D.A. Bushnell, J. Fu, A.L. Gnatt, B. Maier-Davis, N.E. Thompson, R.R. Burgess, A.M. Edwards, P.R. David, R.D. Kornberg, "Architecture of RNA Polymerase II and Implications for the Transcription Mechanism," Science 288, 640 (2000).

2. ALS USERS' MEETING ABSTRACTS DUE NEXT WEEK
(Contacts: alsabstract@lbl.gov)

Tuesday, August 15, is the deadline for ALS users, including students and postdocs, to submit abstracts for the upcoming ALS Users' Meeting. Highlight oral presentations for the Young Researcher session will be selected by the Users' Executive Committee from the abstracts received; other submissions will be presented as posters. The poster sessions will be held in conjunction with the vendor exhibits on Monday, October 16, and Tuesday, October 17. Abstracts can be submitted on line at http://www-als.lbl.gov/als/usermtg/abstracts.html.

General information about the meeting, including a list of workshops proposed for this year's program, can be found at http://www-als.lbl.gov/als/usermtg. Registration and accommodation materials will be mailed out soon.

3. LEAVE YOUR MARK ON THE USERS' MEETING: DESIGN A LOGO
(Contact: ejmoxon@lbl.gov)

ALS users, staff, family, and friends are invited to enter the ALS Users' Meeting logo design contest, sponsored by the ALS Users' Executive Committee. The winning design will be featured on the front of black canvas briefcases that will be given to each attendee of this year's ALS Users' Meeting (October 16-18).

Designs for the briefcase logo should be one color and no larger than 10 by 6 inches (25 by 15 cm). Rough drawings or concepts, as well as more polished artwork, are all acceptable. Enter now, enter often!

Send your designs by Thursday, August 31, to

Elizabeth Moxon
Advanced Light Source
Berkeley Lab, MS 4-230
Berkeley, CA 94720
Fax: (510) 495-2111

4. 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
Phil Huie (Stanford Univ. Medical Center)
Sherry Zhang and Phil Ross (Berkeley Lab)
Shyamsunder Erramilli (Boston Univ.)
Harvey Doner (Univ. of California, Berkeley)
Allen Johnson (Univ. of Nevada, Las Vegas)
Felicia Betancourt and Bob Glaeser (Univ. of California, Berkeley, and Berkeley Lab)
Jessica Preciado, Ralph Greif, and Boris Rubinsky (Univ. of California, Berkeley)

Beamline 7.3.1.1
Boris Sinkovic (Univ. of Connecticut)
Harald Ade (North Carolina State Univ.)
Rainer Fink (Univ. of Wuerzburg, Germany)

Beamline 8.0.1
Tom Callcott (Univ. of Tennessee)
Dave Ederer (Tulane Univ.)
Alexander Moewes (Univ. of Saskatchewan, Canada)

Beamline 9.0.2
Lusi Sheng (Univ. of Science and Technology of China)
Paul M. Guyon (Univ. Paris-Sud)
Hochlauf Majdi (Univ. of Marne-la-Vallee, France)
Melita Morton (Univ. of Chicago)

Beamline 10.0.1
Alfred Muller (Justus-Liebig Univ. Giessen, Germany)
Wilfried Wurth (Technische Univ. Muenchen, Germany)

Beamline 10.3.1
Harvey Doner (Univ. of California, Berkeley)

5. OPERATIONS UPDATE
(Contact: Lampo@lbl.gov)

For the user runs of July 25 - 30 and August 1 - 6, the beam availability was essentially 100%. Both runs were in two-bunch mode at 1.9 GeV. Of the delivered beam, 95% was delivered to completion without interruption. 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 Bruce Samuelson (BCSamuelson@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.