The two subfamilies of rice glutelin differ in both primary and higher-order structures
The two subfamilies of rice glutelin differ in both primary and higher-order structures
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DOI：
10.1016/j.bbapap.2004.02.001
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发表时间：
2004-06-01
影响因子：
3.2
通讯作者：
Utsumi, S
中科院分区：
文献类型：
--
作者：
Katsube-Tanaka, T;Duldulao, JBA;Utsumi, S
稻谷蛋白占稻子总蛋白质的70-80%，由两个营养不同的亚家族（A和B型）组成。虽然两个亚家族之间的初级序列相似性高达60%，但我们建立了在免疫印迹法分析低量抗原时区分两个亚家族的条件。经十二烷基硫酸钠聚丙烯酰胺凝胶电泳（SDS-PAGE）可将glutin a多肽拆分为6个标记为alpha1 ~ alpha6的条带。凝胶过滤分析表明，谷蛋白以聚合形式存在，分子量较小。SDS-PAGE分解多肽的免疫印迹分析显示，alpha2、alpha3和alpha4为A型，并且这些A型和alpha1 （B型）被聚合。除α 1外，两个亚家族的聚合倾向明显不同，通过对α多肽对应谷蛋白cDNA区域的大肠杆菌表达系统分析表明，α 1可能来源于GluB-4。GluB-4和所有A型亚基在高变区有一个额外的Cys残基，对应于多肽的c端区域。因此，额外的Cys残基被假设为谷蛋白聚合的原因。(C) 2004 Elsevier B.V.版权所有
Rice glutelin, which accounts for 70-80% of the total proteins of the seeds, consists of two nutritionally different subfamilies (A and B types). Although the similarity in primary sequences between the two subfamilies is as high as 60%, we established conditions to discriminate the two subfamilies when low amounts of antigen are analyzed by immunoblot methods. The glutelin a polypeptides can be resolved into six bands labeled alpha1 to alpha6 by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Gel filtration analysis showed that glutelin exists as a polymerized and a smaller molecular weight form. Immunoblot analysis of SDS-PAGE resolved polypeptides showed that alpha2, alpha3, and alpha4 are an A type and that these A types as well as alpha1, a B type, are polymerized. The polymerization tendency clearly differed between the two subfamilies except for alpha1, which may be derived from GluB-4 as suggested by analysis using Escherichia coli expression systems of glutelin cDNA regions corresponding to alpha polypeptides. GluB-4 and all the A type subunits have an extra Cys residue in the hypervariable regions, corresponding to the C-terminal region of a polypeptide. Accordingly, the extra Cys residue is hypothesized to be responsible for the polymerization of glutelin. (C) 2004 Elsevier B.V. All rights reserved.