Exploring the biology of O-acetyl sialic acids using stable synthetic mimics

使用稳定的合成模拟物探索 O-乙酰唾液酸的生物学

• 批准号: 9761427
• 负责人: Xi Chen
• 金额: $ 52.22万
• 依托单位: UNIVERSITY OF CALIFORNIA AT DAVIS
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-25 至 2021-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9761427
• 关键词: Acetylation; Aldehyde-Lyases; Apoptosis; Binding; Binding Proteins; Biochemical; Biological; Biological Process; Biology; Cell surface; Cells; Cellular biology; Chemicals; Chemistry; Computing Methodologies; Cultured Cells; Data; Diagnostic; Enzymes; Family; Flow Cytometry; Funding; Ganglioside GD3; Human; Immune; Immunology; Joints; Libraries; Ligands; Link; Lymphocyte Function; Malignant - descriptor; Metabolic; Methods; Modification; Monitor; N-Acetylneuraminate lyase; N-Acetylneuraminic Acid; N-glycolylneuraminic acid; Nature; Neuraminidase; Neurosciences; Outcome; Paper; Pathologic; Pathologic Processes; Pathology; Physiologic pulse; Physiological; Play; Polysaccharides; Process; Proteins; Publishing; Reaction; Research Design; Role; Sialic Acids; Source; Specificity; Structure; Substrate Specificity; System; Testing; Therapeutic; Time; Vertebrates; analog; design; esterase; feeding; member; microbial; microorganism; molecular dynamics; mutant; oncology; pathogenic bacteria; sialylation; tumor; virology

Project Summary Exploring the biology of O-acetyl sialic acids using stable synthetic mimics The term “sialic acid” tends to be used synonymously with N-acetylneuraminic acid (Neu5Ac, often called “NANA”). In fact, Neu5Ac is just the most common member of a diverse family of molecules. O-Acetylated sialic acids are widespread in humans, other vertebrates, and some pathogenic bacteria. The O-acetyl modifications are well known to play key roles in many biological and pathological processes, in fields as diverse as immunology, oncology, virology and neuroscience. However, despite their discovery many decades ago, the study of these modifications has been greatly hampered by their instability. O-Acetyl groups can be hydrolyzed easily by small pH changes or by esterases, and O-acetyl groups at C-7 and C-8 of sialic acids can migrate to C-9, sometimes even under physiological conditions. To date, there is no reliable approach to systematically investigate the cell biology or pathology of sialoglycans containing these labile O-acetyl groups. This proposal brings together for the first time three labs with the combined chemical, biological, and computational expertise to jointly tackle this long-standing problem in a new and systematic way. We hypothesized that substituting O-acetyl on sialic acids by N-acetyl groups is a suitable strategy to provide stable mimics for investigating these important molecules. For proof of principle, we have shown experimentally and computationally that 5,9-di-N-acetylneuraminic acid (Neu5Ac9NAc) is a good mimic of naturally occurring 9-O-acetyl-5-N-acetylneuraminic acid (Neu5,9Ac2) in various types of studies. In the current proposal we will further investigate this molecule, as well as a library of N-acetylneuraminic acid (Neu5Ac) derivatives with N-acetylation at C-4, C-7, or C-8, or with two N-acetyl groups at C-7 and C-9, at C-8 and C-9, or at C-4 and C-9, all representing stable mimics of unstable O-acetylated sialic acids that are known to occur in nature, but have remained underexplored. Sialosides containing these N-acetyl Neu5Ac derivatives will be chemoenzymatically synthesized and used as probes to study the ligand specificity of various sialic acid- binding proteins of mammalian or microbial origin. The structural comparison of O-acetylated sialosides and their N-acetylated counterparts will also be explored by computational methods and by NMR studies. This project will design and generate important approaches to elucidate fundamental mechanisms and biological consequences of sialic acid O-acetylation, opening the door to many previously intractable questions. This, in turn, will help to develop potential diagnostic and therapeutic approaches for infectious, malignant or immune processes involving these common but poorly understood sialic acid forms. In the long run, the approach can be extended to other O-acylated sialic acids in nature such as 9-O-lactyl-Neu5Ac (Neu5Ac9Lt), and O- acetylated forms of non-human N-glycolylneuraminic acid (Neu5Gc) which might be incorporated into humans from exogenous sources.

项目摘要 使用稳定的合成模拟物探索o-乙酰基唾液酸的生物学 术语“唾液酸”倾向于与n-乙酰神经氨酸（neu5ac，通常称为neu5ac）合成使用 “娜娜”）。实际上，neu5ac只是潜水分子家族中最常见的成员。 O-乙酰化 唾液酸在人类，其他脊椎动物和某些致病性细菌中广泛。 O-乙酰基 众所周知，修改在许多生物学和病理过程中起关键作用，在领域中 潜水员作为免疫学，肿瘤学，病毒学和神经科学。但是，他们的发现数十年 以前，对这些修饰的研究受到了它们的不稳定性的严重阻碍。 O-乙酰基可以是 通过小pH变化或酯酶轻松地水解，唾液酸的C-7和C-8的O-乙酰基可以 迁移到C-9，有时甚至在身体状况下。迄今为止，没有可靠的方法 系统地研究含有这些不稳定O-乙酰基的唾液聚糖的细胞生物学或病理学。 该提案首次将三个实验室与化学，生物学和 计算专业知识以新的和系统的方式共同解决这个长期存在的问题。我们 假设N-乙酰基在唾液酸上取代o-乙酰基是一种合适的策略 稳定的模仿来研究这些重要分子。为了证明原则，我们已经表明 通过实验和计算，5,9-Di-N-乙酰神经氨酸（NEU5AC9NAC）是一个很好的模仿 在各种类型的研究中，天然发生的9-O-乙酰-5-N-乙酰神经氨酸（NEU5,9AC2）。在电流中 提案我们将进一步研究该分子以及N-乙酰神经氨酸酸（NEU5AC）的库 在C-4，C-7或C-8处具有N-乙酰化的衍生物，或C-7和C-9的两个N-乙酰基，C-8和C-9，C-9， 或在C-4和C-9处，所有这些都代表已知发生的不稳定的O-乙酰化唾液酸的稳定模拟物 本质上，但仍未得到充实。含有这些N-乙酰基NEU5AC衍生物的唾液酸盐将是 化学酶合成并用作研究各种唾液酸的配体特异性的问题 哺乳动物或微生物起源的结合蛋白。 O-乙酰化的唾液苷和 他们的N-乙酰化对应物也将通过计算方法和NMR研究来探索。这 项目将设计并生成重要的方法来阐明基本机制和生物学 唾液酸o-乙酰化的后果，为许多以前棘手的问题打开了大门。这个，在 转弯，将有助于开发潜在的诊断和治疗方法，以有效，恶性或免疫 过程涉及这些常见但不了解的唾液酸形式。从长远来看，方法可以 在自然界中可以扩展到其他O-酰化唾液酸，例如9-O-lactyl-neu5ac（neu5ac9lt）和O- 非人类n-糖基因神经氨酸（NEU5GC）的乙酰化形式，可以掺入人类 来自外源性来源。