GroEL/GroES cycling: ATP binds to an open ring before substrate protein favoring protein binding and production of the native state.

ABSTRACT: The GroEL/GroES reaction cycle involves steps of ATP and polypeptide binding to an open GroEL ring before the GroES encapsulation step that triggers productive folding in a sequestered chamber. The physiological order of addition of ATP and nonnative polypeptide, typically to the open trans ring of an asymmetrical GroEL/GroES/ADP complex, has been unknown, although there have been assumptions that polypeptide binds first, allowing subsequent ATP-mediated movement of the GroEL apical domains to exert an action of forceful unfolding on the nonnative polypeptide. Here, using fluorescence measurements, we show that the physiological order of addition is the opposite, involving rapid binding of ATP, accompanied by nearly as rapid apical domain movements, followed by slower binding of nonnative

SUBMITTER: Tyagi NK 

PROVIDER: S-EPMC2777187 | biostudies-literature | 2009 Dec

REPOSITORIES: biostudies-literature