ABSTRACT
The problem of protein-folding processes has been the subject of intense research over several decades, and the emerging picture is that the processes are certainly not simple. Small globular proteins seem to fold on their own in an aqueous environment as well as in a cellular environment. In contrast, larger proteins or proteins made up of several components often in the cell require assistance from molecular chaperones, proteins that “help” other proteins to fold. Membrane proteins are another special class that require a special cellular machinery to fold properly. Then one should not forget that an individual protein certainly can misfold and that the cell has the protein degradation functions, for example, the ubiquitin-proteasome pathway, to take care of such situations.
