USE OF BIFUNCTIONAL BIOTINYL COMPOUNDS TO DETERMINE ARRANGEMENT OF SUBUNITS IN AVIDIN
USE OF BIFUNCTIONAL BIOTINYL COMPOUNDS TO DETERMINE ARRANGEMENT OF SUBUNITS IN AVIDIN
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DOI：
10.1042/bj1250781
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发表时间：
1971-01-01
影响因子：
4.1
通讯作者：
VALENTINE, RC
中科院分区：
文献类型：
--
作者：
GREEN, NM;KONIECZNY, L;VALENTINE, RC
合成了一系列双生物素二胺，两个生物素残基的羧基之间有 9 至 25 个键。结果发现，当生物素残基之间的键少于12个时，两个生物素残基中只有一个能够与亲和素结合。具有较长链的化合物以双功能方式表现并产生抗生物素蛋白的线性聚合物，其通过电子显微镜和凝胶过滤进行表征。用短链试剂（12、13或14个键）形成的聚合物相对不稳定，可以被弱结合的生物素类似物解聚。长链试剂的聚合物在这些条件下不会解聚，并且仅缓慢地受到添加的生物素的影响。当试剂的链长达到 23 个键时，聚合物变得更短，表明该试剂现在能够连接同一亲和素分子内的两个亚基。从聚合物的形态可以看出，亲和素分子的四个亚基以222对称性排列，并且在分子短轴的相对两端分成两对，尺寸为55Å×55Å×41Å。
A series of bisbiotinyl diamines was synthesized with between 9 and 25 bonds between the carboxyl groups of the two biotin residues. It was found that only one of the two biotin residues could combine with avidin when there were fewer than 12 bonds between the biotin residues. Compounds with longer chains behaved in a bifunctional manner and gave rise to linear polymers of avidin, which were characterized by electron microscopy and by gel filtration. The polymers formed with the shorter-chain reagents (12, 13 or 14 bonds) were relatively unstable and could be depolymerized by weakly bound analogues of biotin. The polymers of longer-chain reagents were not depolymerized under these conditions and were only slowly affected by added biotin. When the chain length of the reagent reached 23 bonds the polymers became much shorter, suggesting that the reagent was now able to link two subunits within the same avidin molecule. From the morphology of the polymers it could be concluded that the four subunits of the avidin molecules were arranged with 222 symmetry and that they were grouped in two pairs at opposite ends of the short axis of the molecule whose dimensions were 55Å×55Å×41Å.