BIBC 100 Study Guide - Midterm Guide: Protein Disulfide-Isomerase, Prolyl Isomerase, Peptidylprolyl Isomerase A
Document Summary
Lecture 5: molecular mechanisms of assisted protein folding. Proteostasis: cells must maintain functional protein machinery to survive: chaperones: assist with folding. Isomerases: form proper aa isomerization: enzymes: help disulfide bond formation, chaperones: break up protein aggregates, degradation systems: remove fatally misfolded/aggregated proteins. Many enzyme assisted protein folding occurs in er. In adp-bound or nucleotide-free state, the nucleotide-binding domain is connected by a flexible linker to the substrate-binding domain: cleft separating 2 domains from each other, lid domain locks the peptide substrate into the binding pocket. Atp binds to same side, recruiting groes on that side and causing groes on opposite side to be released and release the folded protein on the other side. Groes causes conformational change in which interior of groel becomes hydrophilic to encourage hydrophobic collapse. Encapsulation inside chamber promotes proper folding by eliminating other interactors, spatially limiting folding possibilities, and promoting hydrophobic collapse.
