Two lines of allosteric communication in the oligomeric chaperonin GroEL are revealed by the single mutation Arg196-->Ala.
Two lines of allosteric communication in the oligomeric chaperonin GroEL are revealed by the single mutation Arg196-->Ala.
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寡聚伴侣蛋白 GroEL 中的两条变构通讯线由单一突变 Arg196-->Ala 揭示。
DOI：
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发表时间：
1994
影响因子：
5.6
通讯作者：
A. Horovitz
中科院分区：
文献类型：
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作者：
O. Yifrach;A. Horovitz
GroEL和大肠杆菌DNA聚合酶I的序列同源性，以及这两种蛋白都与腺嘌呤核苷酸结合的事实，向我们暗示它们可能具有相似的核苷酸结合部位。GroEL中的Arg196与DNA聚合酶I中的Arg425相对应，位于其核苷酸结合部位附近。在这里，我们报告了在GroEL中突变Arg196-->；Ala对其动力学和变构性质的显著影响。该突变降低了在野生型GroEL中发现的ATP水解的正协作性。它还会引起强烈的底物(ATP)抑制，而这在野生型蛋白中并不明显。突变的双重效应反映了GroEL中ATP结合位点之间存在两条变构通讯线路，表明存在嵌套协作性。
Sequence homology between GroEL and Escherichia coli DNA polymerase I, together with the fact that both proteins bind adenine nucleotides, suggested to us that they may have a similar nucleotide binding site. Arg196 in GroEL corresponds to Arg425 in DNA polymerase I, which is near its nucleotide binding site. Here, we report the striking effects of the mutation Arg196-->Ala in GroEL on its kinetic and allosteric properties with respect to ATP. The mutation reduces positive co-operativity in ATP hydrolysis found in wild-type GroEL. It also gives rise to strong substrate (ATP) inhibition, which is not apparent in the wild-type protein. The dual effect of the mutation reflects the presence of two lines of allosteric communication between ATP binding sites in GroEL and suggests the existence of nested co-operativity.