BIOC 212 Lecture Notes - Lecture 2: Flippase, Endosome, Dephosphorylation

• School: McGill University
• Department: Biochemistry
• Course: BIOC 212
• Professor: Dieter Reinhardt

Document Summary

Chaperonins are large oligomeric complexes, with a typical double-ring structure. Most work of chaperonins done in bacterial form (groel: double ring structure, oligomeric, very different from hsp70/90. E. coli groel: 2 rings x 7 identical subunits x 60 kda = 840 kda: back to back rings with different conformations, part of the cycle. E. coli groes cap co-chaperone: 7 subunits x 10 kda = 70 kda. Homologs of human mitochondrial hsp60 and hsp10. Acts like a cage, encloses polypeptide substrate. Each groel subunit has an atpase domain and a substrate-binding domain. Substrate-binding domain either binds substrate (down = no nucleotide) or groes atp-bound. In absence of nucleotide, substrate-binding domain in down position. In presence of atp, substrate-binding domain moves up. Rings are identical and work in alternating cycles (in picture, can see cavity formed) Down position of bottom ring (no nucleotide = no. Atp/adp): substrate binding domain in down position.