title: The nucleotide-binding domain 2 of the human transporter protein MRP6.
abstract: Multidrug-resistance-associated protein 6 (MRP6/ABCC6) belongs to the ABC transporter family, whose members share many characteristic features including membrane domains and two nucleotide-binding domains (NBD1 and NBD2). These function cooperatively to bind and hydrolyze ATP for the transport of substrates across biological membranes. In this study, MRP6-NBD2 (residues 1252-1503) was expressed in Escherichia coli, purified and structurally and functionally characterized. CD spectra suggested that the protein is folded. Furthermore, NBD2 is shown to be biologically active as it binds ATP and presents ATPase activity although significantly lower compared with isolated NBD1. The mixture of NBD2 and NBD1 exhibited an activity similar to the NBD2 alone, indicating that NBD1 and NBD2 form a heterodimer with the latter limiting ATP hydrolysis. These findings suggest that NBD1 has a higher tendency to form an active homodimer, which is also supported by in silico analysis of energy-minimized dimers of the homology models of the two domains.
authors: Department of Chemistry "Antonio Mario Tamburro", University of Basilicata, viale Ateneo Lucano 10, 85100 Potenza, Italy. angela.ostuni@unibas.it
authors: Angela
authors: A
authors: Ostuni
authors: Rocchina
authors: R
authors: Miglionico
authors: Magnus
authors: M
authors: Monné
authors: Maria Antonietta
authors: MA
authors: Castiglione Morelli
authors: Faustino
authors: F
authors: Bisaccia
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli; D006801:Humans; D008958:Models, Molecular; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D000255:Adenosine Triphosphate; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D011994:Recombinant Proteins; C102029:ABCC6 protein, human