Unexpected parallels between SaPI replication initiators and conserved SCC ORFs

SaPI 复制启动子和保守的 SCC ORF 之间的意外相似之处

• 批准号: 8873188
• 负责人: PHOEBE A RICE
• 金额: $ 23.7万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-02-01 至 2017-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8873188
• 关键词: ATP phosphohydrolase; ATPase Domain; Address; Adenylyl Imidodiphosphate; Antibiotic Resistance; Appearance; Binding; Biochemical; Biochemistry; Biological Models; Biology; Chromosomes; Complex; Crystallization; Crystallography; DNA; DNA biosynthesis; Data; Data Set; Drug Design; Elements; Enzymes; Event; Excision; Family; Future; Gene Structure; Genes; Genome; Genomic Islands; Homologous Gene; Horizontal Gene Transfer; Housekeeping Gene; L-Selenomethionine; Literature; Medical; Methicillin Resistance; Mobile Genetic Elements; Molecular Biology; Morphology; Open Reading Frames; Pathogenesis; Pathogenicity Island; Pattern; Phase; Proteins; Public Health; Replication Initiation; Replication Origin; Resistance; Site; Staphylococcus aureus; Structure; Superantigens; Testing; Toxin; Variant; Work; base; biochemical tools; clinical practice; ds-DNA; helicase; in vitro activity; in vivo; melting; methicillin resistant Staphylococcus aureus; prevent; public health relevance; recombinase; replication initiator protein; resistance gene

 DESCRIPTION (provided by applicant): This project will investigate a new hypothesis regarding how the mobile genetic element (SCCmec) that carries methicillin resistance spreads among S. aureus strains: We propose that it encodes previously unsuspected functionality for its own replication, which would enhance the efficiency of any horizontal gene transfer mechanism. MRSA (methicillin resistant S. aureus) is a serious and growing public health problem. The recombinases that integrate and excise the SCCmec element into and out of the host genome have been identified and are under study in our lab. However, nothing is known about the events between excision from one genome and appearance in another. While analyzing the conserved ORFs that flank recombinase genes, we realized that some of are likely to have functions in DNA replication. This proposal focuses on a large putative ATPase (Cch) that we discovered is related to the known replication initiation proteins encoded by S. aureus pathogenicity islands (SaPIs). Our preliminary structural and biochemical data suggest that the SCCmec protein in question (Cch) is a self-loading helicase whose closest homologs in the ATPase domain are, surprisingly, the eukaryotic and archaeal replicative MCM helicases. Thus we have determined the first structure of that type of helicase in the active ring form. This work will change how people think about SCCmec elements and how they spread methicillin resistance and will provide new model systems for understanding mechanisms of self-loading and MCM-like helicases. Aim 1: Structural understanding of Cch Aim 2: How structurally similar / different are the subtypes of SaPI / SCC replication initiator? Aim 3: What are the biochemical activities of Cch and SaPI3 rep?

 描述（由适用提供）：该项目将调查一个关于移动遗传元素（SCCMEC）如何携带甲氧西林耐药性在金黄色葡萄球菌菌株之间扩散的新假设：我们建议它为其自身的重复编码以前未经证实的功能，这将提高任何水平基因转移机制的效率。 MRSA（耐甲氧西林的金黄色葡萄球菌）是一个严重且日益严重的公共卫生问题。已经确定了将SCCMEC元素纳入宿主基因组的重组酶，并在我们的实验室中进行了研究。但是，关于一个基因组的惊喜与另一个基因组的惊喜之间的事件一无所知。在分析侧翼重组酶基因的保守ORF时，我们意识到其中一些可能在DNA复制中具有功能。该提案的重点是我们发现的大型假定ATPase（CCH），与已知的复制计划蛋白有关，由金黄色葡萄球菌致病岛（SAPIS）编码。我们的初步结构和生物化学数据表明，所讨论的SCCMEC蛋白（CCH）是一种自载的解旋酶，其ATPase结构域中最接近的同源物是令人惊讶的是真核和存档复制性MCM解放液。我们已经确定了活性环形式的这种类型的解旋酶的第一个结构。这项工作将改变人们对SCCMEC元素的看法以及它们如何传播甲氧西林的耐药性，并将为理解自载和MCM样解旋酶的机制提供新的模型系统。目标1：对CCH目标的结构理解2：SAPI / SCC复制引发剂的结构相似 /不同？目标3：CCH和SAPI3代表的生化活动是什么？