Crystal structure of the Moloney murine leukemia virus RNase H domain
Crystal structure of the Moloney murine leukemia virus RNase H domain
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DOI：
10.1128/jvi.00750-06
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发表时间：
2006-09-01
影响因子：
5.4
通讯作者：
Goff, Stephen P.
中科院分区：
文献类型：
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作者：
Lim, David;Gregorio, G. Glenn;Goff, Stephen P.
对Moloney小鼠白血病病毒(Mo-MLV)核糖核酸酶H结构域进行了结晶学研究，以提供有关其结构和作用机制的信息。这些努力导致了一个突变的Mo-MLV RNaseH的结晶，该突变缺少假定的螺旋C(Delta C)。1.6埃的分辨结构类似于人类免疫缺陷病毒1型(HIV-1)和大肠杆菌RNaseH的已知结构。结构揭示了由高度保守的酸性残基D524、E562和D583组成的催化核心中镁离子的配位。Mo-MLV结构的表面电荷图谱显示，酶的一侧有高密度的碱性电荷。利用与RNA/DNA杂化底物结合的HIV-1逆转录酶结构叠加的Mo-MLV结构模型，研究了Mo-MLV RNaseH二级结构和单个氨基酸在结合底物中的潜在作用。已鉴定的区域包括Mo-MLV核糖核酸酶Hβ1-β2、αA和αB以及从αB到αD及其后续环的残基。大多数已鉴定的亚硫酸盐结合残基与嗜盐芽孢杆菌核糖核酸酶H中的核苷酸直接结合残基相对应，在RNA/DNA的共晶结构中观察到这一残基。最后，将Mo-MLV、E.Coli和HIV-1的RNase H重叠显示，HIV-1连接结构域的一个环位于Mo-MLV和E.ColiC-螺旋的同一区域。HIV-1连接结构域可能起到识别和结合RNA/DNA底物主槽的作用。
A crystallographic study of the Moloney murine leukemia virus (Mo-MLV) RNase H domain was performed to provide information about its structure and mechanism of action. These efforts resulted in the crystallization of a mutant Mo-MLV RNase H lacking the putative helix C (Delta C). The 1.6-angstrom resolution structure resembles the known structures of the human immunodeficiency virus type 1 (HIV-1) and Escherichia coli RNase H. The structure revealed the coordination of a magnesium ion within the catalytic core comprised of the highly conserved acidic residues D524, E562, and D583. Surface charge mapping of the Mo-MLV structure revealed a high density of basic charges on one side of the enzyme. Using a model of the Mo-MLV structure superimposed upon a structure of HIV-1 reverse transcriptase bound to an RNA/DNA hybrid substrate, Mo-MLV RNase H secondary structures and individual amino acids were examined for their potential roles in binding substrate. Identified regions included Mo-MLV RNase H beta 1-beta 2, alpha A, and alpha B and residues from alpha B to alpha D and its following loop. Most of the identified subs trate-binding residues corresponded with residues directly binding nucleotides in an RNase H from Bacillus halodurans as observed in a cocrystal structure with RNA/DNA. Finally, superimposition of RNases H of Mo-MLV, E. coli, and HIV-1 revealed that a loop of the HIV-1 connection domain resides within the same region of the Mo-MLV and E. coli C-helix. The HIV-1 connection domain may serve to recognize and bind the RNA/DNA substrate major groove.