ANALYSIS OF CONSERVED AMINO ACID SEQUENCE MOTIFS IN NTPASES

保守的氨基酸序列基序在不同组的 利用计算机测序方法研究了利用NTP的酶 分析到预测未探索的NTR活性结束 蛋白质，设计用于序列中NTPases鉴定的方案 数据库并生成这种类型的基于序列的分类 酶。 NTPases的特征在于定义明确的保守基序， 涉及底物结合和水解。氨基酸序列 在数据库中搜索所谓的A基序， 磷酸盐结合和由此产生的蛋白质组进行了探索， 关于它们与其他蛋白质的相似性的细节， 关于NTT活动的现有数据。一个新的超家族（假定） 描述了DNA依赖性ATP酶，其包括 原核NtrC相关转录调节因子，涉及的MCM蛋白 在真核DNA复制的起始中， 未表征的细菌和叶绿体蛋白质。MCM蛋白是 显示含有ATP结合基序的修饰形式， 预测介导的ATP依赖性开放的双链DNA在 复制起点在第二次调查中， 证明了未识别的开放阅读帧的产物， 地钱线粒体和酵母，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 III的DNA和RNA解旋酶，以前已知包括 只有小病毒的蛋白质。多重比对的比较 显示NtrC超家族的蛋白质和 超家族III共有三个紧密排列相关序列基序 ATP酶结构域由100 - 150个氨基酸残基组成。 一 类似的保守基序阵列被发现在家庭的 DNA相关的ATP酶据推测，这三大类 核酸依赖性ATP酶具有与核心ATP酶相似的结构 它们都是从一个共同的祖先进化而来。几个以前 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，并预测 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， 使其导出每个大组的识别序列模式。 该项目的意义在于预测NTT活性 对于许多功能未知的蛋白质， NTP结合基序的偏差， 不同类型的NTPases，并开发基于序列的 一个巨大的酶类的分类。

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.