Omtvedt L A, Husby G, Cornwell G G, Kyle R A, Sletten K
Department of Biochemistry/Biotechnology Centre of Oslo, University of Oslo, Norway.
Scand J Immunol. 1997 May;45(5):551-6. doi: 10.1046/j.1365-3083.1997.d01-431.x.
The authors report on the amino acid sequence of the glycosylated amyloid protein AL MS. The amyloid fibrils were extracted from the spleen of a patient (MS.) with amyloidosis. The protein AL MS was purified from the amyloid fibrils by gel filtration. SDS-PAGE performed on the purified protein material showed glycosylated protein bands in the range of 22 to 32 kDa, corresponding to polymerization of N-terminal fragments. The protein was characterized by amino acid analysis and Edman degradation. Tryptic digest combined with Staphylococcal V8 protease, chymotrypsin and pyroglutamate aminopeptidase digestion, as well as cleavage with BNPS-skatole, established the complete amino acid sequence of 168 residues. The protein was compared to other proteins in the SWISSPROT databank, showing homology with the immunoglobulin light chain variable subgroup lamda I. AL MS showed some unique amino acid substitutions. Highly conserved residues Gly(57) and Arg(61), were exchanged to arginine and glutamine, respectively, possibly altering the three- dimensional structure of the protein.
作者报道了糖基化淀粉样蛋白AL MS的氨基酸序列。淀粉样纤维是从一名患有淀粉样变性的患者（MS.）的脾脏中提取的。通过凝胶过滤从淀粉样纤维中纯化出蛋白AL MS。对纯化后的蛋白质材料进行的SDS-PAGE显示，糖基化蛋白条带在22至32 kDa范围内，对应于N端片段的聚合。通过氨基酸分析和埃德曼降解对该蛋白质进行了表征。胰蛋白酶消化结合葡萄球菌V8蛋白酶、胰凝乳蛋白酶和焦谷氨酸氨肽酶消化，以及用BNPS-粪臭素裂解，确定了168个残基的完整氨基酸序列。将该蛋白质与SWISSPROT数据库中的其他蛋白质进行比较，显示与免疫球蛋白轻链可变亚组λI具有同源性。AL MS显示出一些独特的氨基酸取代。高度保守的残基Gly(57)和Arg(61)分别被替换为精氨酸和谷氨酰胺，这可能改变了蛋白质的三维结构。
