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SUMMARY:'What mitochondria learned from their bacterial ancestors: Oxidati
 on-driven protein folding' - Professor Johannes Herrmann\, University of K
 aiserslautern\, Germany
DTSTART:20110119T150000Z
DTEND:20110119T160000Z
UID:TALK28396@talks.cam.ac.uk
CONTACT:Penny Peck
DESCRIPTION:In the bacterial periplasm and in the ER of eukaryotic cells\,
  sulfhydryl oxidases catalyze the formation of disulfide bridges between c
 ysteine residues in order to induce or stabilize protein folding. In contr
 ast\, other cellular compartments are assumed to be generally counteractin
 g the formation of disulfide bridges to maintain proteins in a reduced sta
 te. \n\nIt therefore was completely unexpected when recently a machinery w
 as identified in the intermembrane space of mitochondria that catalyzes th
 e oxidative folding of proteins. This machinery is essential for protein t
 ranslocation of certain cysteine-containing precursor proteins and consist
 s of two components which are highly conserved and essential for viability
 : The oxidoreductase Mia40 and the sulfhydryl oxidase Erv1. Mia40 serves a
 s import receptor that covalently binds to proteins after their passage th
 rough the TOM complex\, thereby converting them to their oxidized state. S
 ince only unfolded\, reduced proteins can traverse the TOM channel\, this 
 irreversibly traps the imported proteins in the mitochondria. Finally\, Mi
 a40 is reoxidized by Erv1. \n\nThus\, the principle to oxidize proteins wa
 s presumably conserved from the bacterial periplasm to the intermembrane s
 pace of mitochondria\, but this system was adapted during evolution so tha
 t it now mediates the vectorial translocation of proteins from the cytosol
  into the organelle. \n
LOCATION:Sackler Lecture Theatre (Level 7)\, Wellcome Trust/MRC Building\,
  Addenbrooke's Site
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