小麦HMW-GS近等基因系不同出粉点面筋二级结构的研究

The Secondary Structure of Glutens from Milled Streams of HMW-GS Near-isogenic Wheat Lines

为给不同出粉点小麦专用粉的开发与利用提供理论依据,应用傅里叶变换红外光谱仪、扫描电镜等技术比较研究了小麦品种西农1330及其Glu-B1位点不同HMW-GS近等基因系(NIL)不同出粉点面筋的二级结构、空间微观结构的差异。面筋蛋白二级结构分析表明,西农1330及其NIL皮磨粉面筋α-螺旋结构和β-转角结构的含量均低于心磨粉,而β-折叠结构的含量均高于心磨粉;同一出粉点面筋蛋白比较发现,含7+8亚基的西农1330NIL的皮磨粉面筋α-螺旋结构和β-转角结构的含量均低于西农1330(含7+9亚基),而β-折叠结构含量高于西农1330,心磨粉面筋二级结构含量则相反。面筋蛋白疏水特性分析表明,小麦皮磨粉面筋蛋白疏水程度均高于心磨粉;同一出粉点小麦面筋蛋白疏水特性分析表明,西农1330NIL的皮磨粉面筋疏水程度较西农1330高,而心磨粉面筋疏水程度较西农1330低。面筋中游离巯基和二硫键含量分析发现,小麦皮磨粉面筋中游离巯基和二硫键含量均高于心磨粉;同一出粉点比较,西农1330NIL的心、皮磨粉面筋游离巯基和二硫键含量均高于西农1330。面筋空间微观结构比较发现,小麦皮磨粉面筋蛋白空间结构均匀,心磨粉面筋蛋白空间结构呈纤维状;同一出粉点西农1330及其NIL的面筋空间微观结构无明显差异。

In order to provide a theoretical basis for the development and utilization of flours at different milling streams,the secondary structure,inter/intra molecules interaction as well as micro structure of reduction and break glutens were studied in the Near-isogenic lines(NIL)with different loci of Glu-B1 from Xinong1330 by FT-Raman Spectroscopy and scanning electron microscope.The results indicated that in different milling streams,the break glutens showed a lower proportion ofα-helix,β-turn and a higher proportion ofβ-sheet than those with reduction glutens.For the break glutens,the proportions ofα-helix,β-turn of Xinong1330 NIL were both lower than those of Xinong1330 and the proportion ofβ-sheet of Xinong1330 NIL was higher than those of Xinong1330,while for the reduction glutens,the contents ofα-helix,β-turn of Xinong1330 NIL were higher than those of Xinong1330 and theβ-sheet content was lower than that of Xinong1330.The break glutens of Xinong1330 and Xinong1330 NIL showed a higher hydrophobicity than reduction glutens.For the break glutens,the hydrophobicity of Xinong1330 NIL was higher than Xinong1330,while for the reduction glutens,the re-sult was the opposite.For free sulfhydryls and disulphide bonds,the content of break glutens was much higher than that of eduction glutens.In comparison with Xinong1330 gluten,a higher amount of free sulfhydryls and disulphide bonds was obtained for Xinong1330 NIL gluten from different milling streams.The break glutens showed a homogeneous network structure,but the reduction glutens showed a more brous structure.There was no significant difference on gluten microstructure between Xinong1330 and Xinong1330 NIL.