Download MendeleyIntegrative Study of the Structural and Dynamical Properties of a KirBac3.1 Mutant: Functional Implication of a Highly Conserved Tryptophan in the Transmembrane Domain.
Fagnen, C., Bannwarth, L., Oubella, I., Zuniga, D., Haouz, A., Forest, E., Scala, R., Bendahhou, S., De Zorzi, R., Perahia, D., Venien-Bryan, C.(2021) Int J Mol Sci 23
- PubMed: 35008764
- DOI: https://doi.org/10.3390/ijms23010335
- Primary Citation of Related Structures:
7ADI - PubMed Abstract:
ATP-sensitive potassium (K-ATP) channels are ubiquitously expressed on the plasma membrane of cells in several organs, including the heart, pancreas, and brain, and they govern a wide range of physiological processes. In pancreatic β-cells, K-ATP channels composed of Kir6.2 and SUR1 play a key role in coupling blood glucose and insulin secretion. A tryptophan residue located at the cytosolic end of the transmembrane helix is highly conserved in eukaryote and prokaryote Kir channels. Any mutation on this amino acid causes a gain of function and neonatal diabetes mellitus. In this study, we have investigated the effect of mutation on this highly conserved residue on a KirBac channel (prokaryotic homolog of mammalian Kir6.2). We provide the crystal structure of the mutant KirBac3.1 W46R (equivalent to W68R in Kir6.2) and its conformational flexibility properties using HDX-MS. In addition, the detailed dynamical view of the mutant during the gating was investigated using the in silico method. Finally, functional assays have been performed. A comparison of important structural determinants for the gating mechanism between the wild type KirBac and the mutant W46R suggests interesting structural and dynamical clues and a mechanism of action of the mutation that leads to the gain of function.
Organizational Affiliation:
IMPMC, UMR 7590, CNRS, Muséum National d'Histoire Naturelle, Sorbonne Université, 75005 Paris, France.
