1. FIRST HIGH-RESOLUTION STRUCTURE FOR AN AQUAPORIN
by Annette Greiner
(Contact: stroud@msg.ucsf.edu)

How can a modest molecule be a great bouncer? Like a heavy at an exclusive night club, an aquaporin can see to it that only the desired molecules enter a cell, stiffly excluding all others. Yet, despite their finickiness, these proteins allow rapid influx of molecules of the right class. Aquaporins are a large family of proteins that selectively yet efficiently transport water or glycerol molecules--but no ions--across membranes in plants, animals, bacteria, and even yeast. Ten of these occur in humans, and more than 150 have been sequenced. But until now, scientists have not had a clear enough view of their structure to understand just how they enforce their exclusivity.

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

Publication about this research: D. Fu, A. Libson, L.J.W. Miercke, C. Weitzman, P. Nollert, J. Krucinski, and R.M. Stroud, "Structure of a glycerol-conducting channel and the basis for its selectivity," Science 290, 481-486 (2000).

2. LAST CALL: PHYSICAL SCIENCES PROPOSALS DUE JUNE 1
(Contact: alsproposals@lbl.gov)

Friday, June 1, 2001, is the deadline for independent investigator proposals in the physical sciences for the running period from December 2001 to May 2002. (This information does not apply to protein crystallography proposals, which have a separate process and schedule.) Scientists wishing to renew a previous proposal must fill in a one-page ALS Experiment Report and Request for Beamtime form and submit it to the User Services Office by the June 1 deadline. The User Services Office has sent email confirmations for all proposals received so far. If you submitted a proposal but have not received confirmation, please contact Bernie Dixon at alsproposals@lbl.gov. The numeric rating for each proposal will be communicated to the investigator along with comments from the Proposal Study Panel, where appropriate. The cutoff rating for each beamline in the previous proposal cycle is published on the Web (see below). The following resources are available for further information:

ALS User Services Administrator

alsuser@lbl.gov

Independent investigator process

http://www-als.lbl.gov/als/quickguide/independinvest.html

Beamline information

http://www-als.lbl.gov/als/als_users_bl/datasheets.html

http://www-als.lbl.gov/als/als_users_bl/bl_table.html

Proposal Study Panel (PSP) scores

http://www-als.lbl.gov/als/quickguide/pspscores.html

3. EIGHT-HOUR, FIXED-TIME TRIAL PERIOD SET
(Contact: B_Feinberg@lbl.gov)

As described in the last issue of ALSNews, we are planning to run for a few months with eight hours between fills and fixed refill times. The first trial of this schedule will commence on June 12 and run through August 20 (with the exception of the July 3-15 two-bunch period, which has its own refill schedule).

During the trial, the storage ring will be refilled at 7:00 a.m., 3:00 p.m., and 11:00 p.m. These times were chosen to avoid both shift changes and the early morning hours. To help remain on schedule, requests for delays of the refill time will be limited to 15 minutes.

In case of beam loss, the storage ring will be immediately refilled, regardless of the time. If it is less than two hours before a scheduled refill, however, that refill will be skipped and the schedule will resume at the next refill hour. Otherwise, the storage ring will be refilled as scheduled. For example, if the beam is lost at 12 noon, the storage ring will be refilled immediately and filled again at 3:00 p.m. However, if the beam is lost between 1:00 p.m. and 3:00 p.m., the storage ring will be refilled immediately and next filled at 11:00 p.m.

Please contact Ben Feinberg (B_Feinberg@lbl.gov, 510-486-7725) if you believe this trial will cause you problems.

4. BERKELEY LAB TO PARTICIPATE IN ENERGY REDUCTION TEST

The State of California will conduct a one-day energy emergency exercise tomorrow, May 24. Local, state, and federal government facilities are being asked to maximize their energy conservation measures during specific time blocks during the day in order to measure the effectiveness of the emergency energy response program. Berkeley Lab and other federal locations will receive a mock Stage 3 Emergency Load Reduction Test notice requesting implementation of short-term conservation measures. The announcement will be issued at around 11 a.m. via email and public address systems. The exercise will conclude at 12:30 p.m.

Measures that employees and on-site users can take include reducing nonessential lighting, turning off computers and printers that are not in use, turning off heating and cooling appliances, unplugging unnecessary personal appliances, and suspending use of copiers and other heavy-use equipment during the test. California's Independent System Operator will monitor the load reduction impact and assess how effective public sector employees can be at saving electricity during peak business hours.

5. USERS' MEETING IN OCTOBER; WORKSHOP DEADLINE JUNE 1
(Contacts: RCPerera@lbl.gov, lindle@nevada.edu)

It's not too early to mark your calendar for this year's ALS Users' Meeting, to be held at Berkeley Lab Monday, October 15, through Wednesday, October 17. The program will again feature oral presentations of ALS science highlights from the past year, as well as reports on recent work from young researchers, a poster session, vendor exhibits, and a keynote speaker. This year, two full days (Tuesday and Wednesday) will be devoted to specialized workshops covering a variety of topics including environmental science, highly correlated electron systems, coherent infrared developments, the synchrotron radiation research theory network (SRRTNet), and x-ray crystallography. Anyone wishing to organize additional workshops should contact Rupert Perera (RCPerera@lbl.gov) or Dennis Lindle (lindle@nevada.edu) by Friday, June 1, 2001.

6. WHO'S IN TOWN: A SAMPLING OF ALS USERS

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

Beamline 1.4.3
Dennis Deen and Miranda Harmon-Smith (Univ. of California, San Francisco)
Hoi-Ying Holman (Berkeley Lab)
T.J. Wilkinson and Dale Perry (Berkeley Lab)
Robin Benedetti and Raymond Jeanloz (Univ. of California, Berkeley)
Felicia Betancourt and Bob Glaeser (Univ. of California, Berkeley, and Berkeley Lab)

Beamline 8.0.1
Eric Fullerton (IBM Almaden Research Center)
Jeff Kortright (Berkeley Lab)
Jonathan Denlinger (Berkeley Lab)
David Shuh (Berkeley Lab)

Beamline 10.0.1
Nora Berrah (Western Michigan Univ.)
John Farley (Univ. of Nevada, Las Vegas)

Beamline 12.0.1
Mike Malinowski (Sandia National Laboratory)
Ken Goldberg and Patrick Naulleau (Berkeley Lab)

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

For the user runs of May 8-13 and May 16-21, the beam reliability (time delivered/time scheduled) was 98%. Of the scheduled beam, 91% 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.

LBNL/PUB-848
Editors: lstamura@lbl.gov, alrobinson@lbl.gov, amgreiner@lbl.gov, ejmoxon@lbl.gov

This work was supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC03-76SF00098.