1lvk
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X-RAY CRYSTAL STRUCTURE OF THE MG (DOT) 2'(3')-O-(N-METHYLANTHRANILOYL) NUCLEOTIDE BOUND TO DICTYOSTELIUM DISCOIDEUM MYOSIN MOTOR DOMAIN
OverviewOverview
Mant (2'(3')-O-(N-methylanthraniloyl)) labeled nucleotides have proven to, be useful tools in the study of the kinetic mechanism of the myosin ATPase, by fluorescence spectroscopy. The sensitivity of the mant fluorophore to, its local environment also makes it suitable to investigate the exposure, of bound nucleotides to solvent from collisional quenching measurements., Here we present the crystal structure of mant-ADP and beryllium fluoride, complexed with Dictyostelium discoideum myosin motor domain (S1dC) at 1.9, A resolution. We complement the structural approach with an investigation, of the accessibility of the mant moiety to solvent using acrylamide, quenching of fluorescence emission. In contrast to rabbit skeletal myosin, subfragment 1, where the mant group is protected from acrylamide (Ksv=0.2, M-1), the fluorophore is relatively exposed when bound to Dictyostelium, myosin motor domain (Ksv= 1.4 M-1). Differences between the Dictyostelium, structure and that of vertebrate skeletal subfragment 1, in the region of, the nucleotide binding pocket, are proposed as an explanation for the, differences observed in the solvent accessibility of complexed, mant-nucleotides. We conclude that protection of the mant group from, acrylamide quenching does not report on overall closure of the nucleotide, binding pocket but reflects more local structural changes.
About this StructureAbout this Structure
1LVK is a Single protein structure of sequence from Dictyostelium discoideum with MG, MNT and BEF as ligands. Full crystallographic information is available from OCA.
ReferenceReference
X-ray crystal structure and solution fluorescence characterization of Mg.2'(3')-O-(N-methylanthraniloyl) nucleotides bound to the Dictyostelium discoideum myosin motor domain., Bauer CB, Kuhlman PA, Bagshaw CR, Rayment I, J Mol Biol. 1997 Dec 5;274(3):394-407. PMID:9405148
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