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SUMMARY:EPFL BioEngineering Talks
DTSTART:20261109T121500
DTEND:20261109T134500
DTSTAMP:20261109T130246Z
UID:4b2eec3ba989380a8938d89bba06eeca95dc84c4b5f01b5641b82675
CATEGORIES:Conferences - Seminars
DESCRIPTION:Invited Speaker and Student Speaker\nWeekly BioEngineering Tal
 ks (Lunch Provided)\n\nINVITED SPEAKER:\n\nArchitecture and Dynamics of Mo
 lecular Machines for Biosynthesis: From Polyketide Assembly to RNA Transcr
 iption\nProf. Jin Young Kang\, Korea Advanced Institute of Science & Tec
 hnology (KAIST)\nHost: Aerin Yang \n\nAbstract:\nCells rely on sophisticat
 ed molecular machines to build molecules ranging from specialized metaboli
 tes to biological macromolecules such as nucleic acids and proteins. Despi
 te acting on chemically distinct substrates\, these systems share the need
  to coordinate catalytic reactions within precisely organized and dynamic 
 macromolecular assemblies. In this seminar\, I will discuss how cryo-elect
 ron microscopy (cryo-EM) reveals both the molecular architectures and reac
 tion dynamics of two such biosynthetic machines.\n\nFirst\, I will present
  cryo-EM structures of the polyketide synthase (PKS) module of ClbB\, a hy
 brid nonribosomal peptide synthetase–polyketide synthase involved in the
  biosynthesis of colibactin\, a gut microbiome-derived genotoxin linked to
  colorectal cancer. The reducing domains of the ClbB PKS module adopt a no
 ncanonical architecture that differs markedly from those of previously cha
 racterized modular PKSs. Its enoylreductase forms a central dimeric scaffo
 ld\, whereas the monomeric dehydratase is positioned at the periphery\, pr
 oducing an unexpected organization of the catalytic domains. Bioinformatic
  analyses further identified related domain organizations across diverse b
 acterial phyla\, suggesting that ClbB represents a broader\, previously un
 recognized class of modular PKSs.\n\nI will then introduce a time-resolved
  cryo-EM platform that we developed using an integrated parylene thin-film
  mixer and sprayer. This platform enables reaction initiation and vitrific
 ation on the millisecond timescale while substantially reducing sample con
 sumption. We are applying it to investigate the nucleotide addition cycle 
 of Escherichia coli RNA polymerase. By sampling the reaction over a 0–40
 0 ms time window\, we seek to determine how closely related transcription 
 intermediates are populated and interconverted during a single round of nu
 cleotide addition cycle. Our initial results reveal a few intermediate sta
 tes that were not observed in conventionally prepared steady-state samples
 \, while also highlighting the analytical challenges associated with resol
 ving transient and structurally similar states.\n\nTogether\, these studie
 s illustrate how cryo-EM can reveal both unexpected architectures of biosy
 nthetic assembly lines and short-lived molecular transitions underlying fu
 ndamental cellular reactions.\n\nBio:\nJin Young Kang is an Associate Prof
 essor in the Department of Chemistry at KAIST\, where her laboratory studi
 es the structure and dynamics of macromolecular machines involved in trans
 cription regulation and natural product biosynthesis. She received her PhD
  from KAIST and trained at The Rockefeller University with Roderick MacKin
 non and Seth Darst before starting her independent group in 2019. Her rese
 arch combines cryo-electron microscopy\, X-ray crystallography\, biochemis
 try\, mass spectrometry\, and computational approaches to understand how d
 ynamic molecular complexes carry out biological functions. Her work has pr
 ovided mechanistic insights into bacterial transcriptional pausing and ter
 mination\, and microbiome-derived colibactin biosynthesis. Her group is al
 so developing time-resolved cryo-EM technologies to capture transient stru
 ctural states and investigate molecular processes in real time.\n\nSTUDENT
  SPEAKER:\n\nTowards riboswitch design by ultradeep sequence-function-mapp
 ing and deep learning \nCharlotte Desczyk\, Jeschek Lab\n\n\n-----------
 -------------------------------------------------------------------\n\nBio
 Engineering Talks mandatory EDBB Seminar Attendance (1st-Year PhD Students
 )\n\n	 Attendance sheet to print HERE \n\nThe BioEngineering Student Sem
 inar Series is an official course for which students can register and earn
  credits.\n \n\n	Register HERE\n	Attendance sheet to print HERE\n\nGenera
 l information:\nIn-person attendance is preferred to support your fellow s
 tudents. Zoom is mainly for students on remote campuses\; please notify Fi
 orella Ghisays in advance and join using your full name.\nIf attending in 
 person\, have your sheet signed after the talk and keep the original\, as 
 no copy is retained.\n 
LOCATION:SV 1717 https://plan.epfl.ch/?room==SV%201717 https://epfl.zoom.u
 s/j/68746410793
STATUS:CONFIRMED
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