Kai Zhang, Li Wang, Yanxin Liu, Kwok-Yan Chan, Xiaoyun Pang, Klaus Schulten,
Zhiyang Dong, and Fei Sun.
Flexible interwoven termini determine the thermal stability of
thermosomes.
Protein & Cell, 4:432-444, 2013.
(PMC: 3740188)
ZHAN2013
Group II chaperonins, which assemble as double-ring complexes, assist in the refolding nascent peptides or denatured proteins in an ATP-dependent manner. The molecular mechanism of group II chaperonin assembly and thermal stability is yet to be elucidated. Here, we selected the group II chaperonins (cpn- and cpn-), also called thermosomes, from Acidianus tengchongensis and investigated their assembly and thermal stability. We found that the binding of ATP or its analogs contributed to the successful assembly of thermosomes and enhanced their thermal stabilities. Cpn- is more thermally stable than cpn-, while the thermal stability of the hetero thermosome cpn- is intermediate. Cryo-electron microscopy reconstructions of cpn- and cpn- revealed the interwoven densities of their non-conserved flexible N/C-termini around the equatorial planes. The deletion or swapping of their termini and pH-dependent thermal stability assays revealed the key role of the termini electrostatic interactions in the assembly and thermal stability the thermosomes.
Download Full Text
The manuscripts available on our site are provided for your personal
use only and may not be retransmitted or redistributed without written
permissions from the paper's publisher and author. You may not upload any
of this site's material to any public server, on-line service, network, or
bulletin board without prior written permission from the publisher and
author. You may not make copies for any commercial purpose. Reproduction
or storage of materials retrieved from this web site is subject to the
U.S. Copyright Act of 1976, Title 17 U.S.C.