Kachi K, Wong P T, French S W
Department of Pathology, Harbor-UCLA Medical Center, Torrance 90509.
Exp Mol Pathol. 1993 Dec;59(3):197-210. doi: 10.1006/exmp.1993.1039.
To study the molecular structure of Mallory body (MB) proteins we applied infrared spectroscopy of the isolated MBs from livers obtained from autopsied patients with alcoholic cirrhosis and griseofulvin-fed (GF-fed) mice. Liver frozen sections were extracted with detergent and digested with deoxyribo- and ribonuclease and collagenase. MB-enriched fractions were then separated out using the aqueous two-phase polymer system. Immunohistochemical and electron microscopic examination showed that the MB composition was virtually identical in human and mouse livers. Infrared spectra of both MB samples showed that the MBs had more numerous and stronger intermolecular hydrogen bonding than did the background control fractions as well as the cytoskeletal fraction from control and GF-fed mice. This may explain why the proteins in MBs are aggregated. The relative amount of beta-sheets was increased compared to the alpha-helices in the MBs, indicating that conformational changes in the cytokeratin peptides of the MBs had occurred. This may explain why the antigenic sites observed in MB proteins show changes in affinity for antibodies to cytokeratins as observed by immunohistochemical staining of MBs.
为研究马洛里小体（MB）蛋白的分子结构，我们对取自酒精性肝硬化尸检患者肝脏及灰黄霉素喂养（GF喂养）小鼠肝脏的分离MB进行了红外光谱分析。肝脏冰冻切片先用去污剂提取，再用脱氧核糖核酸酶、核糖核酸酶和胶原酶消化。然后使用双水相聚合物系统分离出富含MB的组分。免疫组织化学和电子显微镜检查显示，人和小鼠肝脏中MB的组成基本相同。两个MB样品的红外光谱均显示，与背景对照组分以及对照和GF喂养小鼠的细胞骨架组分相比，MB具有更多、更强的分子间氢键。这可能解释了MB中的蛋白质为何会聚集。与MB中的α-螺旋相比，β-折叠的相对含量增加，表明MB中的细胞角蛋白肽发生了构象变化。这可能解释了为何通过MB的免疫组织化学染色观察到，MB蛋白中观察到的抗原位点对细胞角蛋白抗体的亲和力发生了变化。
