利用质谱技术结合EST库搜索鉴定厚壳贻贝新型足丝蛋白(英文)

Characterization of Novel Byssal Proteins from Mytilus coruscus by Shotgun Mass Spectrometry

贻贝利用足丝粘附于水下各种基质表面.作为一种具有优异粘附性能的生物材料,贻贝足丝蛋白在新型水下粘附剂及表面保护涂层的研制与开发中具有重要的仿生学意义.目前,已报道的贻贝足丝蛋白分子达11种,但是仍然有更多的足丝蛋白分子不为人知.为进一步探讨贻贝足丝蛋白的分子多样性,并从中筛选具有特殊生物学功能的足丝蛋白分子,本文采用鸟枪法-液相色谱-质谱/质谱技术(shotgun-LC-MS/MS)对厚壳贻贝足丝蛋白进行了蛋白质组学分析.将厚壳贻贝足丝分为足丝纤维和足丝盘两部分,每一部分均采用醋酸-尿素溶液,以及醋酸-盐酸胍溶液进行蛋白质抽提;抽提后的足丝蛋白经胰蛋白酶酶解,利用线性离子阱四级杆质谱(LTQ)进行鸟枪法质谱分析.二级质谱图(MS/MS)用以搜索公共数据库中的贻贝表达序列标签(expressed sequence tag,EST)数据库.采用上述方法,获得14种贻贝新型足丝蛋白的高可信度结果及其所匹配的部分或全长cDNA序列;经结构域分析,发现上述新型贻贝足丝蛋白分子的序列中多数包含各种类型的结构域,包括胶原蛋白结构域、C1Q结构域、C1Q结合结构域、微管蛋白辅助折叠结构域、蛋白酶拮抗结构域、VWA结构域、几丁质酶结构域等.在此基础上,对上述新型足丝蛋白在贻贝足丝形成以及粘附方面的功能进行了推测.上述结果对进一步了解贻贝足丝的分子组成以及粘附机理奠定了基础.

Mussels attach to submerged surfaces using byssus, which contains proteins to be considered as novel wet adhesives and coatings for biomedical applications. Eleven byssal proteins have been identified, yet the full protein composition of Mytilus byssus are not well understood. In this study, a proteomic approach was developed for screening new byssal proteins from Mytilus coruscus. The two parts of byssal thread and byssal plaque were extracted by acid-urea/acid-guanidine-chloride and subjected to shotgun-LC-MS/MS analyses. The results were searched against the expressed sequence tag （EST） sequence database for Mytilus. Partial or full-length sequences of 14 novel byssal proteins of transcripts were identified. Based on the sequence and domain analysis, these novel byssal proteins are implied to be used for adhesion of byssus.