06/14/2010
Understanding D-Xylose Isomerase Using X-rays and Neutrons
Summary
Converting biomass to fuels on a large scale will require optimizing enzymes that transform breakdown-resistant biomass components into forms that are easy to change into fuel molecules. The enzyme xylose isomerase (XI) is especially important because it can convert sugars that resist bioconversion to fuel into sugars that are readily fermented by, for example, yeasts. A new study led by scientists at Los Alamos National Laboratory (LANL) has shown how the structure around the active site of XI changes as it carries out the conversion. The research used neutron diffraction experiments at the Protein Crystallography Station at the Lujan Center at LANL to map the positioning of individual hydrogen atoms as XI moves them from one carbon to another on the sugar molecule. The research team was able to model how specific amino acids in the XI structure are involved in the movement of the protons. The results may enable new approaches to modifying the enzyme to improve its performance for biofuel and other applications. The new study is published in the June issue of Structure and is featured on the cover of the issue. The research was led by Paul Langan of LANL and included scientists at six other universities and institutes in the United States, France and the United Kingdom.
References
A.Y. Kovalevsky, et al., “Metal Ion Roles and the Movement of Hydrogen during Reaction Catalyzed by D-Xylose Isomerase: A Joint X-Ray and Neutron Diffraction Study,” Structure 18, 688-699 (2010).