Jiang X, Myatt E, Lykos P, Stevens F J
Center for Mechanistic Biology and Biotechnology, Argonne National Laboratory, Argonne, Illinois 60439, USA.
Biochemistry. 1997 Oct 28;36(43):13187-94. doi: 10.1021/bi970408h.
Amyloidosis is a pathological process in which normally soluble proteins polymerize to form insoluble fibrils (amyloid). Amyloid formation is found in a number of diseases, including Alzheimer's disease, adult-onset diabetes, and light-chain-associated amyloidosis. No pharmaceutical methods currently exist to prevent this process or to remove the fibrils from tissue. The search for treatment and prevention methods is hampered by a limited understanding of the biophysical basis of amyloid formation. Glycosaminoglycans (GAGs) are long, unbranched heteropolysaccharides composed of repeating disaccharide subunits and are known to associate with amyloid fibrils. The interaction of amyloid-associated free light chains with GAGs was tested by both size-exclusion high-performance liquid chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis experiments. The results indicated that heparin 16 000 and chondroitin sulfate B and C precipitated both human intact light chains and recombinant light chain variable domains. Although all light chains interacted with heparin, the strongest interactions were obtained with proteins that had formed amyloid. Molecular modeling indicated the possibility of interaction between heparin and the conserved saddlelike surface of the light chain dimer opposite the complementarity-determining segments that form part of the antigen-binding site of a functional antibody. This suggestion might offer a new path to block the aggregation of amyloid-associated light chain proteins, by design of antagonists based on properties of GAG binding. A hexasaccharide was modeled as the basis for a possible antagonist.
淀粉样变性是一种病理过程，在此过程中，正常情况下可溶的蛋白质聚合成不溶性纤维（淀粉样蛋白）。在许多疾病中都发现有淀粉样蛋白形成，包括阿尔茨海默病、成人发病型糖尿病和轻链相关淀粉样变性。目前尚无药物方法来阻止这一过程或从组织中清除纤维。由于对淀粉样蛋白形成的生物物理基础了解有限，治疗和预防方法的探索受到了阻碍。糖胺聚糖（GAGs）是由重复二糖亚基组成的长链、无分支杂多糖，已知其与淀粉样纤维相关。通过尺寸排阻高效液相色谱法和十二烷基硫酸钠-聚丙烯酰胺凝胶电泳实验测试了淀粉样相关游离轻链与GAGs的相互作用。结果表明，肝素16 000以及硫酸软骨素B和C沉淀了人完整轻链和重组轻链可变结构域。虽然所有轻链都与肝素相互作用，但与已形成淀粉样蛋白的蛋白质相互作用最强。分子建模表明，肝素与轻链二聚体保守的鞍状表面之间存在相互作用的可能性，该表面与构成功能性抗体抗原结合位点一部分的互补决定区相对。这一推测可能为基于GAG结合特性设计拮抗剂来阻断淀粉样相关轻链蛋白的聚集提供一条新途径。一种六糖被建模为可能的拮抗剂的基础。
