Takata Takumi, Shimo-Oka Tadashi, Kojima Masami, Miki Kunio, Fujii Noriko
Research Reactor Institute, Kyoto University, Kumatori-cho, Sennan, Osaka 590-0494, Japan.
Biochem Biophys Res Commun. 2006 May 26;344(1):263-71. doi: 10.1016/j.bbrc.2006.03.126.
Although proteins are generally composed of l-alpha-amino acids, d-beta-aspartic acid (Asp)-containing proteins have been reported in various elderly tissues. Our previous study detected several d-beta-Asp-containing proteins in a rabbit lens derived from epithelial cell line by Western blot analysis of a 2D-gel using a polyclonal antibody that is highly specific for d-beta-Asp-containing proteins. The identity of each spot was subsequently determined by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and the Ms-Fit online database searching algorithm. In this study, we discovered novel d-beta-Asp-containing proteins from rabbit lens. The results indicate that beta-crystallin A3, beta-crystallin A4, beta-crystallin B1, beta-crystallin B2, beta-crystallin B3, gamma-crystallin C, gamma-crystallin D, and lambda-crystallin in rabbit lens contain d-beta-Asp residues. Furthermore, the occurrence of d-beta-Asp residues increases with infrared ray (IR) irradiation. Additionally, some d-beta-Asp-containing proteins only appear after IR irradiation. One such protein is the alpha-enolase, which shows homology to tau-crystallin.
虽然蛋白质通常由L-α-氨基酸组成，但在各种老年组织中已报道了含D-β-天冬氨酸（Asp）的蛋白质。我们之前的研究通过使用对含D-β-Asp的蛋白质具有高度特异性的多克隆抗体对二维凝胶进行蛋白质印迹分析，在源自上皮细胞系的兔晶状体中检测到了几种含D-β-Asp的蛋白质。随后通过基质辅助激光解吸/电离飞行时间质谱和Ms-Fit在线数据库搜索算法确定了每个斑点的身份。在本研究中，我们从兔晶状体中发现了新的含D-β-Asp的蛋白质。结果表明，兔晶状体中的β-晶状体蛋白A3、β-晶状体蛋白A4、β-晶状体蛋白B1、β-晶状体蛋白B2、β-晶状体蛋白B3、γ-晶状体蛋白C、γ-晶状体蛋白D和λ-晶状体蛋白含有D-β-Asp残基。此外，D-β-Asp残基的出现随着红外线（IR）照射而增加。此外，一些含D-β-Asp的蛋白质仅在IR照射后出现。其中一种蛋白质是α-烯醇化酶，它与τ-晶状体蛋白具有同源性。
