 |
PDBsum entry 4i5o
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Motor protein
|
PDB id
|
|
|
|
4i5o
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
References listed in PDB file
|
|
|
Key reference
|
|
|
Title
|
|
Nucleotide binding and conformational switching in the hexameric ring of a aaa+ machine.
|
|
|
Authors
|
|
B.M.Stinson,
A.R.Nager,
S.E.Glynn,
K.R.Schmitz,
T.A.Baker,
R.T.Sauer.
|
|
|
Ref.
|
|
Cell, 2013,
153,
628-639.
[DOI no: ]
|
|
|
PubMed id
|
|
|
|
|
|
Abstract
|
|
|
ClpX, a AAA+ ring homohexamer, uses the energy of ATP binding and hydrolysis to
power conformational changes that unfold and translocate target proteins into
the ClpP peptidase for degradation. In multiple crystal structures, some ClpX
subunits adopt nucleotide-loadable conformations, others adopt unloadable
conformations, and each conformational class exhibits substantial variability.
Using mutagenesis of individual subunits in covalently tethered hexamers
together with fluorescence methods to assay the conformations and
nucleotide-binding properties of these subunits, we demonstrate that dynamic
interconversion between loadable and unloadable conformations is required to
couple ATP hydrolysis by ClpX to mechanical work. ATP binding to different
classes of subunits initially drives staged allosteric changes, which set the
conformation of the ring to allow hydrolysis and linked mechanical steps.
Subunit switching between loadable and unloadable conformations subsequently
isomerizes or resets the configuration of the nucleotide-loaded ring and is
required for mechanical function.
|
|
|
|
|
|
|
