STRUCTURAL STUDIES ON SOLUBLE AND MEMBRANE BOUND PROTEINS INVOLVED IN METABOLISM

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. The glycerol metabolic pathway is a fundamental biochemical pathway, crucial to the biosynthesis of essential cellular components and for energy production. Functionally, the uptake of glycerol relies on the cytoplasmic glycerol kinase (GlpK), which provides the chemical driving force for the non-ATP dependent uptake of glycerol. Enhanced glycerol uptake is mediated through the membrane-channel formed by the glycerol facilitator (GlpF). Another membrane protein, the glycerol-3-phosphate (G3P) dehydrogenase (GlpD), oxidizes glycerol-3-phosphate to dihydroxyacetone phosphate, which can be utilized in energy production via the glycolytic pathway and provides reducing equivalents to Enzyme III of the mitochondrial respiratory chain. Additionally, the GlpD can synthesize G3P for the biosynthesis of the glycerophospholipids that are incorporated into cellular membranes. A soluble homolog of the GlpD is the glycerophosphate oxidase (GlpO), which catalyzes the same reaction of oxidizing G3P to DHAP and also plays a role in respiration through the G3P shuttle that recycles reducing equivalents to the mitochondrial electron transport chain. Consequently, all of these enzymes play highly important roles in biosynthetic pathways and in energy production. Comprehensive structural studies are proposed.