Jobling Stephen A
Agriculture Flagship, Commonwealth Scientific Industrial Research Organisation, Canberra, Australian Capital Territory 2601, Australia. E-mail:
Sci Adv. 2015 Jun 12;1(5):e1500069. doi: 10.1126/sciadv.1500069. eCollection 2015 Jun.
The cereal cell wall polysaccharide (1-3,1-4)-β-glucan is a linear polymer of glucose containing both β1-3 and β1-4 bonds. The structure of (1-3,1-4)-β-glucan varies between different cereals and during plant growth and development, but little is known about how this is controlled. The cellulose synthase-like CslF6 protein is an integral membrane protein and a major component of the (1-3,1-4)-β-glucan synthase. I show that a single amino acid within the predicted transmembrane pore domain of CslF6 controls (1-3,1-4)-β-glucan structure. A new mechanism for the control of the polysaccharide structure is proposed where membrane pore architecture and the translocation of the growing polysaccharide across the membrane control how the acceptor glucan is coordinated at the active site and thus the proportion of β1-3 and β1-4 bonds within the polysaccharide.
谷物细胞壁多糖（1-3,1-4）-β-葡聚糖是一种含有β1-3和β1-4键的葡萄糖线性聚合物。（1-3,1-4）-β-葡聚糖的结构在不同谷物之间以及植物生长发育过程中有所不同，但对于其如何被调控却知之甚少。类纤维素合酶CslF6蛋白是一种整合膜蛋白，也是（1-3,1-4）-β-葡聚糖合酶的主要成分。我发现CslF6预测跨膜孔结构域内的单个氨基酸控制着（1-3,1-4）-β-葡聚糖的结构。本文提出了一种控制多糖结构的新机制，即膜孔结构以及生长中的多糖跨膜转运控制着受体葡聚糖在活性位点的配位方式，进而控制多糖中β1-3和β1-4键的比例。
