Daniel T. Murray

Area of research

Materials Chemistry · Molecular Biology

Research interest

Research topics from publications: Small-angle neutron scattering solution structures of NADPH-dependent sulfite reductase; Structure–Function Relationships in the Oligomeric NADPH-Dependent Assimilatory Sulfite Reductase; Neutron scattering maps the higher-order assembly of NADPH-dependent assimilatory sulfite reductase; Domain crossover in the reductase subunit of NADPH-dependent assimilatory sulfite reductase; Domain Swapping in the Reductase Subunit of Nadph-Dependent Assimilatory Sulfite Reductase. Representative work: The central step in the assimilation of sulfur is a six-electron reduction of sulfite to sulfide, catalyzed by the oxidoreductase NADPH-dependent assimilatory sulfite reductase (SiR). SiR is composed of two subunits. One is a multidomain flavin binding reductase (SiRFP) and the other an iron-containing oxidase (SiRHP). Both enzymes are primarily globular, as expected from their functions as redox enzymes. Consequently, we know a fair amount about their structures but not how they assemble. Curiously, both structures have conspicuous regions that are structurally undefined, leaving questions about their functions and raising the possibility that they are critical in forming the larger complex ABSTRACT Sulfite reductase (SiR), a dodecameric complex of flavoprotein reductase subunits (SiRFP) and hemoprotein oxidase subunits (SiRHP), reduces sulfur reduction for biomass incorporation. Electron transfer within SiR requires intra- and inter-subunit interactions that are mediated by the relative position of each protein, governed by flexible domain movements. Using small-angle neutron scattering, we report the first solution structures of SiR heterodimers containing a single copy of each subunit. These structures show how the subunits bind and how both subunit binding and oxidation state impact SiRFP’s conformation. Neutron contrast matching experiments on selectively deuterated hetero