THE SEQUENCE STATISTICS AND SOLUTION CONFORMATION OF A BARLEY (1-]3, 1-]4)-BETA-D-GLUCAN
THE SEQUENCE STATISTICS AND SOLUTION CONFORMATION OF A BARLEY (1-]3, 1-]4)-BETA-D-GLUCAN
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DOI：
10.1016/0008-6215(86)85065-0
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发表时间：
1986-12-01
影响因子：
3.1
通讯作者：
FINCHER, GB
中科院分区：
文献类型：
--
作者：
BULIGA, GS;BRANT, DA;FINCHER, GB
40°的序列统计和水溶液构象。使用已知的 (1.fwdarw.3) 和 (1.fwdarw.4) 连接序列分布、理论构象分析和聚合物链构象的统计力学理论，对从大麦 (Hordeum vulgare) 中分离的水溶性 (1.fwdarw.3,1.fwdarw.4)-.β.-D-葡聚糖进行了实际建模。该大麦 β-葡聚糖级分由 (1.fwdarw.4)-β-低聚葡萄糖组成，主要是 d.p.。 4个或更少，由单个β-(1.fwdarw.3)连接连接。序列统计的近似处理不考虑d.p的(1.fwdarw.4)-.β-葡萄糖低聚糖的小摩尔分数(约2％)。 .apprx.10 显着低估了溶液中的链延伸。当这些较长的、高度延伸的(1.fwdarw.4)-β-低聚葡萄糖片段包含在以实验观察到的比例随机合并所有(1.fwdarw.4)-β-低聚葡萄糖片段的模型中时，实现了对观察到的链延伸的正确预测。链条灵活性在 40° 范围内。水溶性β-葡聚糖级分主要由分离的β-(1.fwdarw.3)键产生；两个或更多个连续的β-(1.fwdarw.3)连接的嵌段提供了额外的灵活性的来源，其可以影响含有显着比例的此类序列的大麦β-葡聚糖级分的性质。
The sequence statistics and aqueous solution conformation of the 40.degree. water-soluble (1.fwdarw.3,1.fwdarw.4)-.beta.-D-glucan isolated from barley (Hordeum vulgare) have been modeled realistically using the known sequence-distributions of (1.fwdarw.3) and (1.fwdarw.4) linkages, theoretical conformational analysis, and the statistical mechanical theory of polymer-chain conformation. This barley .beta.-glucan fraction consists of (1.fwdarw.4)-.beta.-glucooligosaccharides, predominantly of d.p. 4 or less, joined by single .beta.-(1.fwdarw.3) linkages. Approximate treatments of the sequence statistics which do not take into account the small mole fraction (.apprx.2%) of (1.fwdarw.4)-.beta.-glucooligosaccharides of d.p. .apprx.10 significantly underestimate the chain extension in solution. A correct prediction of the observed chain extension is achieved when these longer, highly extended (1.fwdarw.4)-.beta.-glucooligosaccharide blocks are included in a model which randomly incorporates all (1.fwdarw.4)-.beta.-glucooligosaccharide segments in the proportions observed experimentally. Chain flexibility in the 40.degree. water-soluble .beta.-glucan fraction is shown to arise principally from the isolated .beta.-(1.fwdarw.3) linkages; blocks of two or more contiguous .beta.-(1.fwdarw.3) linkages provide a source of additional flexibility which may influence the properties of barley .beta.-glucan fractions containing a significant proportion of such sequences.