The yeast type I topoisomerase Top3 interacts with Sgs1, a DNA helicase homolog: a potential eukaryotic reverse gyrase
The yeast type I topoisomerase Top3 interacts with Sgs1, a DNA helicase homolog: a potential eukaryotic reverse gyrase
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DOI：
10.1128/mcb.14.12.8391-8398.1994
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发表时间：
1994-12
影响因子：
5.3
通讯作者：
S. Gangloff;J. McDonald;C. Bendixen;Louise M. Arthur;R. Rothstein
中科院分区：
文献类型：
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作者：
S. Gangloff;J. McDonald;C. Bendixen;Louise M. Arthur;R. Rothstein
我们之前已经证明，在酿酒酵母中编码一种类似原核生物的I型拓扑异构酶的基因TOP3突变的细胞表现出多向表型，包括生长缓慢和基因组不稳定。我们发现了一个突变，sgs1（慢生长抑制因子），它抑制生长缺陷和top3突变体基因组不稳定性的增加。在这里，我们报道了SGS1基因在与Top3相互作用的蛋白筛选中的独立分离。DNA序列分析表明，推测的Sgs1蛋白与大肠杆菌recQ基因编码的解旋酶高度同源。这些结果表明，Sgs1产生了一种有害的拓扑底物，Top3优先分解。Sgs1解旋酶同源物和Top3拓扑异构酶的相互作用让人想起最近描述的酸硫藻（Sulfolobus acidocalarius）反旋酶的结构，其中I型DNA拓扑异构酶和解旋酶样结构域融合在单个多肽中。
We have previously shown that cells mutant for TOP3, a gene encoding a prokaryotic-like type I topoisomerase in Saccharomyces cerevisiae, display a pleiotropic phenotype including slow growth and genome instability. We identified a mutation, sgs1 (slow growth suppressor), that suppresses both the growth defect and the increased genomic instability of top3 mutants. Here we report the independent isolation of the SGS1 gene in a screen for proteins that interact with Top3. DNA sequence analysis reveals that the putative Sgs1 protein is highly homologous to the helicase encoded by the Escherichia coli recQ gene. These results imply that Sgs1 creates a deleterious topological substrate that Top3 preferentially resolves. The interaction of the Sgs1 helicase homolog and the Top3 topoisomerase is reminiscent of the recently described structure of reverse gyrase from Sulfolobus acidocaldarius, in which a type I DNA topoisomerase and a helicase-like domain are fused in a single polypeptide.