PUBLICATION
Estimating the true stability of the prehydrolytic outward-facing state in an ABC protein
- Authors
- Simon, M.A., Iordanov, I., Szollosi, A., Csanády, L.
- ID
- ZDB-PUB-231013-48
- Date
- 2023
- Source
- eLIFE 12: (Journal)
- Registered Authors
- Keywords
- D-loop, composite ATP-binding site, flickery closure, molecular biophysics, mutant cycle, structural biology, xenopus, zebrafish
- MeSH Terms
-
- Cystic Fibrosis Transmembrane Conductance Regulator*/metabolism
- Catalytic Domain
- Adenosine Triphosphate*/metabolism
- Humans
- Mutation
- Ion Channel Gating
- PubMed
- 37782012 Full text @ Elife
Citation
Simon, M.A., Iordanov, I., Szollosi, A., Csanády, L. (2023) Estimating the true stability of the prehydrolytic outward-facing state in an ABC protein. eLIFE. 12:.
Abstract
CFTR, the anion channel mutated in cystic fibrosis patients, is a model ABC protein whose ATP-driven conformational cycle is observable at single-molecule level in patch-clamp recordings. Bursts of CFTR pore openings are coupled to tight dimerization of its two nucleotide-binding domains (NBDs) and in wild-type (WT) channels are mostly terminated by ATP hydrolysis. The slow rate of non-hydrolytic closure - which determines how tightly bursts and ATP hydrolysis are coupled - is unknown, as burst durations of catalytic site mutants span a range of ~200-fold. Here, we show that Walker A mutation K1250A, Walker B mutation D1370N, and catalytic glutamate mutations E1371S and E1371Q all completely disrupt ATP hydrolysis. True non-hydrolytic closing rate of WT CFTR approximates that of K1250A and E1371S. That rate is slowed ~15-fold in E1371Q by a non-native inter-NBD H-bond, and accelerated ~15-fold in D1370N. These findings uncover unique features of the NBD interface in human CFTR.
Genes / Markers
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Orthology
Engineered Foreign Genes
Mapping