Single-stranded DNA binding activity of XPBI, but not XPBII, from Sulfolobus tokodaii causes double-stranded DNA melting
Single-stranded DNA binding activity of XPBI, but not XPBII, from Sulfolobus tokodaii causes double-stranded DNA melting
复制标题
来自托科代硫化叶菌的 XPBI（而非 XPBII）的单链 DNA 结合活性导致双链 DNA 熔化
DOI：
10.1007/s00792-010-0338-z
复制
发表时间：
2011-01-01
期刊：
影响因子：
2.9
通讯作者：
Shen, Yulong
中科院分区：
文献类型：
--
作者：
Ma, Xiaoqing;Hong, Ye;Shen, Yulong
XPB解旋酶是转录因子IIH（transcription factor IIH，TFIIH）的最大亚基，是真核生物中转录起始和核苷酸切除修复（nucleotide excision repair，NER）所必需的10个亚基蛋白复合物。两个XPB同源物（XPBI和XPBII）存在于大多数crenarchaeota的基因组中，crenarchaeota是古细菌的两个主要门之一;然而，其生化特性尚未完全表征，其细胞作用尚未明确定义。在这里，我们报告说，XPBI从超嗜热crenarcheon硫化叶菌tokodaii（StoXPBI）是能够不稳定的双链DNA（dsDNA）螺旋ATP（指定为dsDNA熔化活性）。这种活性被单链DNA（ssDNA）抑制，并且依赖于StoXPBI的独特N-末端结构域，其也可能负责StoXPBI的内在强ssDNA结合活性，如缺失分析所揭示的。我们证明，StoXPB Ⅱ的ATP酶活性显着刺激StoXPB Ⅱ的核酸酶伴侣StoXPB 1。讨论了XPBI独特的dsDNA解链活性在古菌NER中的作用。
XPB helicase is the largest subunit of transcription factor IIH (TFIIH), a ten-subunit protein complex essential for transcription initiation and nucleotide excision repair (NER) in Eukarya. Two XPB homologues (XPBI and XPBII) are present in the genome of most crenarchaeota, one of the two major phyla of archaea; however, the biochemical properties have not been fully characterized and their cellular roles have not been clearly defined. Here, we report that XPBI from the hyperthermophilic crenarchaeon Sulfolobus tokodaii (StoXPBI) is able to destabilize double-stranded DNA (dsDNA) helix independent of ATP (designated as dsDNA melting activity). This activity is inhibited by single-stranded DNA (ssDNA) and relies on the unique N-terminal domain of StoXPBI, which is also likely responsible for the intrinsic strong ssDNA binding activity of StoXPBI as revealed by deletion analysis. We demonstrate that the ATPase activity of StoXPBII is remarkably stimulated by StoBax1, a nuclease partner of StoXPBII. The role of the unique dsDNA melting activity of XPBI in NER in archaea was discussed.