The California Tech [email protected] VOLUME CXVI NUMBER 4 PASADENA , CALIFORNIA TE C H .C ALTE C H .EDU OC TOBER 22, 2012 Modeling reveals protein channel’s function KIMM FESENMAIER are needed because Caltech Science Writer the proteins that are synthesized at Chemists at the Caltech have ribosomes must managed, for the first time, to travel to other simulate the biological function of regions of the cell a channel called the Sec translocon, or outside the cell which allows specific proteins to in order to perform pass through membranes. The feat their functions; required bridging timescales from however, the cellular the realm of nanoseconds all the membranes prevent way up to full minutes, exceeding even the smallest of the scope of earlier simulation molecules, including efforts by more than six orders of water, from passing magnitude. The result is a detailed through them willy- molecular understanding of how nilly. In many ways, the translocon works. channels such as the Modeling behavior across very Sec translocon serve different timescales is a major as gatekeepers—once challenge in modern simulation the Sec translocon research. “Computer simulations determines that a often provide almost uselessly given protein should detailed information on a timescale be allowed to pass that is way too short, from which through, it opens you get a cartoon, or something up and allows the that might raise as many questions protein to do one as it answers,” says Thomas Miller, of two things: to be an assistant professor of chemistry integrated into the at Caltech. “We’ve managed to go membrane, or to be significantly beyond that, to create secreted completely a tool that can actually be compared out of the cell. against experiments and even push Scientists have experiments—to predict things disagreed about how that they haven’t been able to see.” the fate of a given The new computational model protein entering and the findings based on its the translocon is results are described by Miller and determined. Based graduate student Bin Zhang in the on experimental current issue of the journal Cell evidence, some Reports. have argued that a The Sec translocon is a channel protein’s amino-acid in cellular membranes involved in sequence is what the targeting and delivery of newly matters—that is, how made proteins. Such channels many of its The ribosome (red, blue) in complex with the translocon channel (green), which is embedded in the cell membrane (yel- amino acids low, white). Proteins that are inserted via the ribosome into the channel can either be laterally integrated into or secreted across the cell membrane (inset). i n t e r a c t -Bin Zhang and Thomas Miller In this issue f a v o r a b l y with water and how many the extremely slow rate at which Other researchers have shown suggesting that kinetic effects can clash. This argument a ribosome adds proteins to that slowing down the rate of also play a role. treats the process as one the channel can be considered protein insertion into the channel NEWS in equilibrium, where infinitely slow. actually changes the outcome, Continued on page 3 North Kitchen ice cream machine3 passes away News briefs from around the globe Helping readers burst out of the Caltech bubble OPINION Nina examines the efficiency of the4 !""#$%&$'(&)! !!!!!!!!!!!!!"!!*++!#$%&'!()$*+!+,-!#$%.&!+,/'!#--0!1!+$2/3'!'$%+-&!4%$5!6$$&!+$!)(&! Techer )7!!"#$!#%"$8&'!$ FEATURE ,&-#.($/&012$.134."#.$51&%$$**!2-$2.-!(%%-'+-&9!+(%6-+'!/:3.*&-&!+,-!;<=<!85)(''7!/:!>55(:!!!!!!!!?@AB! Call for new ushers 67.($58&%&3&5$8"152$5&&-$9**:+++!%(/'-&!4$%!'$*2!0/+3,-:!(4+-%!$%/6/:(.!&$:$%'!#/+,&%-#!!!!!!?CAB! at Beckman 6 ;&5"$(.<"2$(")$2.0(%2!!! =!3,$'-:!/:!(++-52+!+$!%-D/D-!E(+,$./3!4(/+,!(5$:6!4$..$#-%'!!!!!!!!!!?F$G!H-#'B! >.2%-&$<.'"2$.55".-.(?"$@A!17-(%I$.&!4$%5-%!2%-'/&-:+!$4!E*)(!5--+'!-GIJA!$4!J-:-K*-.(!!!!!!!?HLMB! SPORTS Women’s volleyball B&-<"-$2"(.%&-$#0"2$ C+!17-(%I$.&!N-$%6-!O3N$D-%:!'-%D-&!('!(!P-5!/:!=$*+,!P(0$+(!!!!!!!!?EHHB! takes a win 7 D"E.("2"$&//0?0.1$'011"#$$ F!&-(&!(4+-%!)$5)/:6!/:!Q-)(:$:9!;=!D$#'!+$!,-.2!/:D-'+/6(+-!!!!!!!!!!!!!!!!!!!?RREB! G&<0?0#"$0($H02?&(20($ I!&-(&!(:&!S!/:T*%-&!/:!O/.#(*0--!'2(!',$$+/:69!/:3.*&/:6!',$$+-%!!!!!!?EHHB! ! THE CALIFORNIA TECH 2 OC TOBER 22, 2012 NEWS Food with Mannion! ASCIT Minutes Minutes for October 18th, 2012. Taken by Allika Do you like eating food? Walvekar How about free food at nice restaurants? Ever want to tell the world exactly what you think of Officers present: Diego Caporale, Christian Rivas, Pushpa Neppala, Mario Zubia, Michelle Tang, Puikei said food? Cheng, Allika Walvekar The Tech will be beginning a new column to chroni- Officers Absent: cle the foodie experiences of new writers every other week...The Catch: They’ll be going head-to-head with Call to Order: 8:41 Tom Mannion who will be reviewing the same restau- President’s Report (Diego): Diego would like to rant. If you have ever thought you were more of a gour- remind the student body that it is responsible for the mand than our resident master chef, now’s your chance upkeep of houses. Any damage accrued is reported to the deans. Diego would like to remind everyone that to prove it! ASCIT meetings are open to the public, and this term Email us for a spot on the list at [email protected] they are at 8:30PM in SAC 15. If you have something specific to discuss email the secretary at sec@donut. caltech.edu so the topic can be added to the agenda. The California Tech Officers’ Reports: Secretary (Allika): Talked to DevTeam about Caltech 40-58, Pasadena, CA 91125 advertising e-mail: [email protected] Write an ASCIT Screening Room Reservation system on editorial e-mail: [email protected] Donut. Designed a new poster for the Olive Walk with descriptions of the various BoD positions. Will be Editors-in-Chief Jonathan Schor articles finalizing the design in the coming week. Stanford Schor Social Director (Michelle): Met with Big I reps News Editor Sandhya Chandrasekaran to discuss their budget. Fall Harvest moved to 11/10. for the Dabney Drag Show, Fleming Frosh Party, and Page Sports Editor Interhouse are all coming up soon. Amol Kamat Tech Treasurer (Puikei): Continuing to fund for Big I. Puikei will now approach Graduate Student Council (GSC), Student Affairs, and smaller companies with Caltech Alums for funding. Director of Operations (Mario): Club funding will take place on 10/21. Clubs have to turn in their Staff Nina Budaeva registration 10/19. The results of Club funding will Casey Handmer Yang Hu be announced once club approval has finished. The Jonathan Ikpeazu Rebecca Lawler assignment of the new club storage will be included in Mary Nguyen Eugene Vinitsky the club funding process. If the clubs absolutely cannot Caroline Yu Chris Zheng attend Club funding on 10/21, they can come to the ASCIT meeting on 10/25 instead. V.P. of Non-Academic Affairs (IHC Chair: Christian): Rotation happened quite smoothly. The Deans received the statistics that compared freshmen’s choices with the house they actually rotated in. Overall, most people were very satisfied with the house Circulation Manager they were put in. Michael Paluchniak V.P. of Academic Affairs (ARC Chair: Pushpa): Advisor Richard Kipling Interviewing frosh reps on 10/20. Pushpa would like to emphasize that the course complaint box should The Tech is published weekly except dur- ing vacation and examination periods by be used for specific, tangible issues that the student the Associated Students of the California Institute of Technology, Inc. The opinions expressed herein are strictly those of the has towards a class, rather than general derogatory authors and advertisers. Letters and submissions are welcome; comments that are difficult act upon. Lucas Carreno e-mail submissions to [email protected] as plain-text attachments, including the has been reinstated to the ARC. Puspha is working author’s name, by Friday of the week be- fore publication. The Tech does accept anonymous contributions under special with the alumni association to facilitate alumni circumstances. The editors reserve the right to edit and abridge all submissions for any feedback for the SFC. reason. All written work remains property of its author. The advertising deadline is 5 PM Friday; all advertising should be submitted elec- tronically or as camera-ready art, but The Agenda for Thursday Oct 18 Meeting: Tech can also do simple typesetting and arrangement. All advertising inquiries get paid up to $30 - ASCIT Meet & Greet should be directed to the business manager at [email protected]. For subscription information, please send mail to “Subscrip- tions.” Meeting Adjourned: 9:54 THE CALIFORNIA TECH NEWS OC TOBER 22, 2012 3 Obituary: Farewell to delicious Dreyer’s North House ice cream machine spurts out its last frozen treat JONATHAN WEBSTER to some serious health issues, stopped making the tubes that fit CDS Associate Director North Kitchen Dreyer’s Machine this very special machine). Alas, moved to the warmer climate of the North Kitchen Dreyer’s Machine North Kitchen Dreyer’s Caltech campus in 2007, working must cease its service to the world. Machine dispensed its last part time to pay for its room and North Kitchen Dreyer’s serving of soft-serve Friday board. Machine leaves a legacy of cold “ North Kitchen Dreyer’s Machine was stubborn as a mule and strong as an ox. When one of its chambers blew out in an unfortunate ultimate Frisbee accident, it went on serving three flavors as though nothing was wrong. October 19, 2012. North North Kitchen Dreyer’s Machine deliciousness that would be hard for Kitchen Dreyer’s Machine was stubborn as a mule and strong any machine to follow.