Mechanism of Action of Group II Chaperonins:

Reißmann, Stefanie (2007): Mechanism of Action of Group II Chaperonins:: Impact of the Built-in Lid on the Conformational Cycle. Dissertation, LMU München: Faculty of Biology

Abstract

Chaperonins are highly allosteric double-ring ATPases that mediate cellular protein folding. ATP binding and hydrolysis control opening and closing of the central chaperonin chamber which transiently provides a protected environment for protein folding. During evolution, two distinct strategies to close the chaperonin chamber have emerged. Archaeal and eukaryotic chaperonins contain a built-in lid, whereas bacterial chaperonins use a ring-shaped cofactor as a detachable lid. The present work contributes to the current mechanistical understanding of group II chaperonins by unraveling key functions of the built-in lid. In addition to physically encapsulating the substrate, the lid-forming apical protrusions also play a key role in regulating chaperonin function and ensuring its activity as a “two-stroke” molecular machine. By comparative investigation of two distinct chaperonin systems, namely TRiC and Mm-Cpn, this study uncovers a remarkable degree of mechanistic and functional conservation between group II chaperonins from eukaryotic and archaeal origin, despite their evolutionary distance.

• Item Type: Theses (Dissertation, LMU Munich)
• Keywords: chaperonin, allostery, protein folding
• Subjects: 500 Natural sciences and mathematics; 500 Natural sciences and mathematics > 570 Life sciences
• Faculties: Faculty of Biology
• Language: English
• Date of oral examination: 24. July 2007
• 1. Referee: Böck, August
• Signature of the printed copy: 0001/UMC 16412