Work

Estimating the true stability of the prehydrolytic outward-facing state in an ABC protein

Year: 2023

Type: article

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.

Source: eLife

DOI: 10.7554/elife.90736

Authors: Márton A. Simon, Iordan Iordanov, András Szöllősi, László Csanády

Institutions: Semmelweis University, Hungarian Research Network

Language: English

Topic: Cystic Fibrosis Research Advances

Subfield: Pulmonary and Respiratory Medicine

Field: Medicine

Domain: Health Sciences

Open Access status: gold

Estimated APC paid: $2,500