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
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发表时间：
1994-12-01
影响因子：
5.3
通讯作者：
ROTHSTEIN, R
中科院分区：
文献类型：
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作者：
GANGLOFF, S;MCDONALD, JP;ROTHSTEIN, R
我们之前已经证明，TOP3（酿酒酵母中编码类原核生物的 I 型拓扑异构酶的基因）的细胞突变体表现出多效性表型，包括生长缓慢和基因组不稳定。我们发现了一种突变，sgs1（慢生长抑制因子），它可以抑制 top3 突变体的生长缺陷和增加的基因组不稳定性。在这里，我们报告了在筛选与 Top3 相互作用的蛋白质时独立分离的 SGS1 基因。 DNA序列分析表明，假定的Sgs1蛋白与大肠杆菌recQ基因编码的解旋酶高度同源。这些结果意味着 Sgs1 产生了 Top3 优先分解的有害拓扑底物。 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来自酸热硫化叶菌的反向旋转酶结构，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, it 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.