Mixed linkage (1,3;1,4)-β-glucan (MLG) is a major non-cellulosic polysaccharide of the commelinid monocot cell walls and an important soluble dietary fibre component found in abundance in cereals. Yet despite its importance, relatively little is known about the molecular mechanism involved in the synthesis and assembly of this polysaccharide. Using functional genomics, the commelinid-specific Cellulose Synthase-Like (CSL) F, CSLH and CSLJ multi-gene families within the larger CAZy GT2 family have been identified as encoding the catalytic components of the MLG synthase enzyme (1-3). We have adopted a multi-disciplinary approach, including molecular, biochemical, proteomic and computational techniques to study CSLF6, the major MLG synthase in grasses. We have built homology models of various GT2 enzymes based upon the recently crystallised bacterial cellulose synthase BcsA (5-6) and have used molecular dynamics (MD) simulations to shed light on what protein features play a role in determining the specificity and sequence of the glycosidic linkages within this polysaccharide synthase family. We will present computational findings as well as experimental data relating protein structure to function. In addition, we will reveal biochemical evidence as to the modes of regulation of CSLF6.
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