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SUMMARY:Chaperone Machineries in RuBisCO Biogenesis and Metabolic Repair -
  Prof. Manajit Hayer-Hartl. Max Planck Institute of Biochemistry\, Germany
DTSTART:20161116T130000Z
DTEND:20161116T140000Z
UID:TALK69175@talks.cam.ac.uk
CONTACT:Howard Griffiths
DESCRIPTION:Ribulose 1\,5-bisphosphate carboxylase/oxygenase (RuBisCO) is 
 not only the most abundant protein in nature but also one with a remarkabl
 y high chaperone requirement for its biogenesis and metabolic maintenance.
 \n\nAlthough by the mid-1990s it was clear that the chaperonin system is r
 equired for the folding of the large subunit of RuBisCO\, the enzyme could
  not be reconstituted in vitro. In 2007\, the structure and mechanism of a
 ction of the first specific assembly chaperone of RuBisCO\, the protein Rb
 cX\, was reported. More recently\, analysis of the protein Raf1 showed tha
 t this protein\, like RbcX\, is also involved in the assembly of RuBisCO. 
 Interestingly\, the mechanisms by which RbcX and Raf1 assist RuBisCO assem
 bly differ substantially.\n\nTo become catalytically active\, the newly-as
 sembled RuBisCO must first be carbamylated by a non-substrate CO2 molecule
  at the active-site lysine and bind a Mg2+ ion as cofactor. Premature bind
 ing of the substrate ribulose-1\,5-biphosphate (RuBP) results in an inacti
 ve complex. Inactivation of RuBisCO also occurs during its multistep catal
 ytic reaction\, due to the production of ‘misfire’ products such as Xu
 BP or PDBP. Reactivation is catalyzed by a AAA+ (ATPases Associated with v
 arious cellular Activities) protein called RuBisCO activase (Rca). More re
 cently\, the discovery of the phosphatase XuBPase\, which hydrolyzes the i
 nhibitory sugar phosphate XuBP\, demonstrated the importance of a function
 al cooperation of Rca with specific phosphatases in maintaining RuBisCO ac
 tivity during photosynthesis.\n\n
LOCATION:Department of Plant Sciences\, Large Lecture Theatre
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