We also stand together for the complete, verifiable and irreversible dismantlement of North Korea's nuclear weapons, and we agreed to reinforce our cooperation on security and defence, including on disarmament and non-proliferation.
A fully denatured protein lacks both tertiary and secondary structure, however, the primary protein sequence remains intact and the protein exists as a random coil (Figure 2.39). Under certain conditions some proteins can refold; however, in many cases, denaturation is irreversible. Cells sometimes protect their proteins against the denaturing influence of heat with enzymes known as heat shock proteins (a type of chaperone), which assist other proteins both in folding and in remaining folded (Figure 2.40). Heat shock proteins are expressed in response to elevated temperatures or other stresses. Some proteins never fold in cells at all except with the assistance of chaperones which either isolate individual proteins so that their folding is not interrupted by interactions with other proteins or help to unfold misfolded proteins, allowing them to refold into the correct native structure. This function is crucial to prevent the risk of precipitation into insoluble amorphous aggregates. 781b155fdc