GroEL-GroES-mediated protein folding requires an intact central cavity

摘要: The chaperonin GroEL is an oligomeric double ring structure that, together with the cochaperonin GroES, assists protein folding. Biochemical analyses indicate that folding occurs in a cis ternary complex which substrate sequestered within central cavity underneath GroES. Recently, however, studies of “minichaperones” containing only apical binding subdomain have questioned functional importance encapsulation GroEL-GroES complexes. Minichaperones were reported to assist despite fact they are monomeric and therefore cannot form cavity. Here we compare directly activity minichaperones full system. In agreement earlier studies, some proteins. However, this effect observed under conditions where substantial spontaneous also indistinguishable from resulting addition nonchaperone α-casein. By contrast, GroE system efficiently promotes several substrates essentially no observed. These data argue requires intact complex, light previous underscore for providing environment distinct bulk solution.