ANALYSIS OF PROLINE RICH PROTEINS FROM HUMAN SALIVA

人类唾液中富含脯氨酸的蛋白质的分析

• 批准号: 7369223
• 负责人: Frank G Oppenheim
• 金额: $ 0.09万
• 依托单位: BOSTON UNIVERSITY MEDICAL CAMPUS
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-07-01 至 2007-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7369223
• 关键词: ANALYSIS; PROLINE; RICH; PROTEINS; HUMAN

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Proline-rich proteins (PRPs) are a family of salivary proteins present in abundant amounts in human parotid and submandibular/sublingual secretions and account for 10-40% of the proteins in these secretions (Kousvelari et al., 1980; Baum et al., 1982; Mandel & Bennick 1983). On the basis of their chemical properties, they are divided into three groups, acidic, basic and glycosylated PRPs. The acidic PRPs are a group of eight structurally closely related molecules with pIs between 4 and 5 (Oppenheim et al., 1971; Bennick and Connell, 1971; Hay et al., 1988). PIFs, PRP1, PRP2 contain 150 residues and have the same amino acid sequence except at positions 4 and 50, which are either aspartic acid or asparagine. PIFf, PRP3 and PRP4 are composed of 106 residues and are identical with the N-terminal 106 residues of PIFs, PRP1 and PRP2, respectively. Genetic studies revealed that the sequence of PRP ?Pa? is identical to PIFs except for the residue at position 27 where leucine substitutes for isoleucine and the residue at position 103 where cysteine substitutes for arginine (Azen et al., 1987). Another acidic PRP characterized by genetic analysis was the ?Db? protein that would contain an extra 21 amino acid repeat of residues 61-81 of PIFs resulting in a 171-amino acid residue polypeptide chain (Azen et al., 1987). The acidic PRPs exhibit unusual biochemical characteristics. They are rich in the amino acids glycine, proline, glutamine and glutamic acid. Amino acid sequencing and chemical analysis has shown that both the serines at residues 8 and 22 are phosphorylated in PIFs, PIFf, PRP1, PRP2, PRP3 and PRP4. Due to the high degree of sequence homology and close pI values of PRPs, separation of these proteins requires chromatography with extremely high resolution and usually involves at least two steps, using a combination of gel filtration and anion-exchange chromatographic techniques. This purification scheme is not only cumbersome, but often results in protein contaminants and unwanted protein loss. Furthermore, these procedures make it impractical to quantitate different PRPs in a number of individuals. The present investigation has resulted in the development of a one step procedure to separate the 8 acidic PRP isoforms and characterized the primary structure and post-translational modifications of the Pa and Db proteins. A manuscript reporting these results will be submitted shortly.

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。脯氨酸富蛋白（Proline-rich proteins, PRPs）是一个唾液蛋白家族，大量存在于人腮腺和下颌下/舌下分泌物中，占这些分泌物中蛋白质的10-40% （Kousvelari et al., 1980; Baum et al., 1982; Mandel & Bennick 1983）。根据其化学性质，将其分为酸性、碱性和糖基化三大类。酸性PRPs是一组由8个结构密切相关的分子组成，其pi值在4到5之间（Oppenheim et al., 1971; Bennick and Connell, 1971; Hay et al., 1988）。pif、PRP1、PRP2含有150个残基，除第4位和第50位为天冬氨酸或天冬酰胺外，它们具有相同的氨基酸序列。PIFf、PRP3和PRP4由106个残基组成，分别与pif、PRP1和PRP2的n端106个残基相同。遗传学研究表明，PRP ？爸爸?除了27号位置亮氨酸取代异亮氨酸和103号位置半胱氨酸取代精氨酸的残基之外，与pif完全相同（Azen et al, 1987）。另一种经遗传分析表征的酸性PRP是？德国联邦铁路(Db) ?该蛋白含有pif残基61-81的额外21个氨基酸重复，从而形成171个氨基酸残基多肽链（Azen et al., 1987）。酸性PRPs表现出不同寻常的生化特征。它们富含氨基酸甘氨酸、脯氨酸、谷氨酰胺和谷氨酸。氨基酸测序和化学分析表明，残基8和22的丝氨酸在pif、PIFf、PRP1、PRP2、PRP3和PRP4中均被磷酸化。由于PRPs的序列高度同源性和pI值接近，分离这些蛋白质需要极高分辨率的色谱，通常涉及至少两步，使用凝胶过滤和阴离子交换色谱技术的组合。这种纯化方案不仅繁琐，而且经常导致蛋白质污染物和不需要的蛋白质损失。此外，这些程序使得对许多个体的不同prp进行量化变得不切实际。目前的研究已经开发出一种一步分离8种酸性PRP异构体的方法，并表征了Pa和Db蛋白的一级结构和翻译后修饰。报告这些结果的手稿将很快提交。