ANALYSIS OF CONSERVED AMINO ACID SEQUENCE MOTIFS IN NTPASES

不同类群中的保守氨基酸序列基序 用计算机测序方法研究了NTP利用酶 未探明的NTPase活性预测末期分析 蛋白质，设计序列鉴定NTPase的方案 数据库并生成此类型的基于序列的分类 酶的作用。 NTPase的特征是定义良好的保守基序 与底物结合和水解有关。氨基酸序列 在数据库中搜索所谓的A主题，它涉及到 磷酸盐结合和由此产生的一组蛋白质在 关于它们与其他蛋白质的相似性的详细信息，以及 关于NTPase活动的现有数据。一个新的(假定的)超级家族 描述了DNA依赖的ATPase，包括ATPase结构域 原核生物NTRC相关转录调控因子、MCM蛋白的参与 在启动真核DNA复制的过程中，以及一组 未鉴定的细菌和叶绿体蛋白质。MCM蛋白是 显示含有修饰形式的ATP结合基序，并且是 预测介导依赖于ATP的双链DNA在 复制源。在第二条调查中，它是 证明了不明开放阅读框的产物来自 Marchantia线粒体和酵母，以及杆状病毒的一个结构域 参与病毒DNA复制的蛋白质与超家族有关 DNA和RNA解旋酶的III，以前已知包括 只有小病毒的蛋白质。多条路线的比较 研究表明，NTRC超家族的蛋白质和解旋酶 超级家族III共有三个紧密结合的相关序列基序 由100-150个氨基酸残基组成的ATPase结构域。一个 类似的保守基序排列也发现于 DNAA相关的ATPase。据推测，这三大集团 核酸依赖的ATPase与核心ATPase的结构相似 并从一个共同的祖先进化而来。之前的几个 未鉴定的蛋白质显示含有保守的序列基序 典型的解旋酶超家族I或II，并被预测为 具有解旋酶活性。DNA和RNA的一般分类 概述了基于序列比较的解旋酶，并尝试 以推导出每个大组的识别序列模式。 该项目的意义在于对NTPase活性的预测 对于许多未知功能的蛋白质，Allowed的特征 NTP结合基序的偏差，识别模式的推导 不同组的NTPase，并以序列为基础的发展 一大类酵素的分类。

Conserved amino acid sequence motifs in different groups of NTP-utilizing enzymes were studied using computer methods of sequence analysis to the end of predicting NTPase activity of unexplored proteins, designing schemes for identification of NTPases in sequence databases and generating a sequence-based classification of this type of enzymes. NTPases are characterized by well-defined conserved motifs that are implicated in substrate binding and hydrolysis. Amino acid sequence databases were searched for the so-called A motif that is involved in phosphate binding and the resulting set of proteins was explored in detail with respect to their similarities with other proteins, and the available data on NTPase activity. A new superfamily of (putative) DNA-dependent ATPases was described that includes the ATPase domains of prokaryotic NtrC-related transcription regulators, MCM proteins involved in the initiation of eukaryotic DNA replication, and a group of uncharacterized bacterial and chloroplast proteins. MCM proteins were shown to contain a modified form of the ATP-binding motif and are predicted to mediate ATP-dependent opening of double-stranded DNA in the replication origins. In a second line of investigation, it was demonstrated that the products of unidentified open reading frames from Marchantia mitochondria and from yeast, and a domain of a baculovirus protein involved in viral DNA replication are related to the superfamily III of DNA and RNA helicases that previously has been known to include only proteins of small viruses. Comparison of the multiple alignments showed that the proteins of the NtrC superfamily and the helicases of superfamily III share three related sequence motifs tightly packed in the ATPase domain that consists of 100 - 150 amino acid residues. A similar array of conserved motifs was found in the family of DnaA-related ATPases. It is hypothesized that the three large groups of nucleic acid-dependent ATPases have similar structure of the core ATPase domain and have evolved from a common ancestor. Several previously uncharacterized proteins were shown to contain conserved sequence motifs typical of the helicase superfamilies I or II and were predicted to possess helicase activity. A general classification of DNA and RNA helicases based on sequence comparison was outlined and an attempt was made to derive identifying sequence pattern for each large group. The significance of the project is in the prediction of NTPase activity for many proteins with unknown functions, characterization of allowed deviations in NTP-binding motifs, derivation of identifying patterns for different groups of NTPases, and development of a sequence-based classification for a vast enzyme class.