title: Phosphorylation-dependent changes in nucleotide binding, conformation, and dynamics of the first nucleotide binding domain (NBD1) of the sulfonylurea receptor 2B (SUR2B).
abstract: The sulfonylurea receptor 2B (SUR2B) forms the regulatory subunit of ATP-sensitive potassium (KATP) channels in vascular smooth muscle. Phosphorylation of the SUR2B nucleotide binding domains (NBD1 and NBD2) by protein kinase A results in increased channel open probability. Here, we investigate the effects of phosphorylation on the structure and nucleotide binding properties of NBD1. Phosphorylation sites in SUR2B NBD1 are located in an N-terminal tail that is disordered. Nuclear magnetic resonance (NMR) data indicate that phosphorylation of the N-terminal tail affects multiple residues in NBD1, including residues in the NBD2-binding site, and results in altered conformation and dynamics of NBD1. NMR spectra of NBD1 lacking the N-terminal tail, NBD1-ΔN, suggest that phosphorylation disrupts interactions of the N-terminal tail with the core of NBD1, a model supported by dynamic light scattering. Increased nucleotide binding of phosphorylated NBD1 and NBD1-ΔN, compared with non-phosphorylated NBD1, suggests that by disrupting the interaction of the NBD core with the N-terminal tail, phosphorylation also exposes the MgATP-binding site on NBD1. These data provide insights into the molecular basis by which phosphorylation of SUR2B NBD1 activates KATP channels.
authors.affiliation: From the Department of Chemical and Physical Sciences, University of Toronto Mississauga, Mississauga, Ontario L5L 1C6, the Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, and.
authors.forename: Elvin D
authors.initials: ED
authors.lastname: de Araujo
authors.affiliation: From the Department of Chemical and Physical Sciences, University of Toronto Mississauga, Mississauga, Ontario L5L 1C6, the Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, and.
authors.forename: Claudia P
authors.initials: CP
authors.lastname: Alvarez
authors.affiliation: From the Department of Chemical and Physical Sciences, University of Toronto Mississauga, Mississauga, Ontario L5L 1C6, the Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, and the Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada.
authors.forename: Jorge P
authors.initials: JP
authors.lastname: López-Alonso
authors.affiliation: From the Department of Chemical and Physical Sciences, University of Toronto Mississauga, Mississauga, Ontario L5L 1C6, the Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, and.
authors.forename: Clarissa R
authors.initials: CR
authors.lastname: Sooklal
authors.affiliation: From the Department of Chemical and Physical Sciences, University of Toronto Mississauga, Mississauga, Ontario L5L 1C6, the Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, and the Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada.
authors.forename: Marijana
authors.initials: M
authors.lastname: Stagljar
authors.affiliation: From the Department of Chemical and Physical Sciences, University of Toronto Mississauga, Mississauga, Ontario L5L 1C6, the Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, and the Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada voula.kanelis@utoronto.ca.
authors.forename: Voula
authors.initials: V
authors.lastname: Kanelis
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D000818:Animals; D017868:Cyclic AMP-Dependent Protein Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D015640:Ion Channel Gating / Q000502:physiology; D019906:Nuclear Magnetic Resonance, Biomolecular; D010766:Phosphorylation / Q000502:physiology; D017434:Protein Structure, Tertiary; D051381:Rats; D064233:Sulfonylurea Receptors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: C577512:Abcc9 protein, rat; D064233:Sulfonylurea Receptors; D000255:Adenosine Triphosphate; D017868:Cyclic AMP-Dependent Protein Kinases
keywords: ABC transporter; conformational change; nuclear magnetic resonance (NMR); phosphorylation; potassium channel; protein dynamic