Origins of Substrate Specificity for the ppGalNAcTs

ppGalNAcT 底物特异性的起源

• 批准号: 7035883
• 负责人: ANJALI S GANGULI
• 金额: $ 2.27万
• 依托单位: UNIVERSITY OF CALIFORNIA BERKELEY
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-03-01 至 2006-08-15
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7035883
• 关键词: enzyme substrate; glycopeptides; glycoprotein structure; glycoproteins; glycosylation; lectin; peptide library; postdoctoral investigator; posttranslational modifications; protein binding; protein structure function; site directed mutagenesis

DESCRPITION (provided by applicant): Mucin-type O-linked glycosylation is a post-translational modification in which proteins are highly decorated by carbohydrate chains. These oligosaccharides serve as mediators of information between cells and are crucial for cell-cell communication. Changes in expression patterns of mucin-type O-linked glycoproteins is believed to contribute to both the invasive and metastatic properties of tumor cells. The biosynthesis of mucin is initiated by a family of enzymes collectively known as the ppGaINAcTs. Characterization of ppGaINAcT substrate specificity and the properties conferring this specificity for each individual isoform has been a difficult task. We propose to use a unique combination of chemistry and molecular biology to facilitate the further understanding of this enzyme family in a stepwise process. Aim 1. Synthesize and systematically analyze a library of glycopeptides to determine the substrate preference of each ppGaINAcT isoform. Aim 2. Create chimeric enzymes to determine what parts of the protein are responsible for conferring specificity. Finally, Aim 3. To correlate the specificity patterns for various isoforms observed in vitro with substrate preference within cells.

描述（由申请方提供）：粘蛋白型O-连接糖基化是一种翻译后修饰，其中蛋白质被碳水化合物链高度修饰。这些低聚糖作为细胞之间的信息媒介，对于细胞与细胞之间的通讯至关重要。粘蛋白型O-连接糖蛋白表达模式的变化被认为有助于肿瘤细胞的侵袭性和转移性。粘蛋白的生物合成由统称为ppGaINAcTs的酶家族启动。表征 ppGaINAcT底物特异性和赋予每种单独同种型这种特异性的性质的研究一直是一项艰巨的任务。我们建议使用一种独特的化学组合 和分子生物学，以促进进一步了解这个酶家族在一个逐步的过程。目标1.合成并系统分析糖肽文库，以确定每种ppGaINAcT亚型的底物偏好。目标2.创造嵌合酶，以确定蛋白质的哪些部分负责赋予特异性。最后，目标3。将体外观察到的各种亚型的特异性模式与细胞内的底物偏好相关联。