Spólnik Paweł, Piekarska Barbara, Stopa Barbara, Konieczny Leszek, Zemanek Grzegorz, Rybarska Janina, Król Marcin, Nowak Mateusz, Roterman Irena
Institute of Medical Biochemistry, Collegium Medicum, Jagiellonian University, Cracow, Poland.
Med Sci Monit. 2003 Apr;9(4):BR145-53.
Frequently observed structural deviations of myeloma-derived immunoglobulins affect polypeptide chain packing and domain stability, enhancing their tendency to aggregate, with all the clinical consequences. Congo red complexation with myeloma immunoglobulins is proposed in this work as a general test to disclose the instability of these proteins. The large ribbon-like supramolecular ligands of Congo red form complexes with proteins by adhesion to beta-conformation polypeptide chains, if allowed to make contact with their backbone interfaces. This can occur in the case of myeloma-derived immunoglobulins with deficient polypeptide chain packing.
MATERIAL/METHODS: Specially adapted two-dimensional agarose electrophoresis of serum proteins, which allows the transient contact of Congo red and serum proteins during migration, was used to reveal the presence of protein components amenable to ligand penetration and binding. The combination of electrophoresis and Congo red binding to proteins permits the removal of loosely attached dye and evaluation of the effective complexation properties of the immunoglobulin fraction directly in the serum.
Comparative studies of dye complexation with two L chains having different reactivities with Congo red confirmed that dye binding depended on protein instability in the conditions used. Myeloma proteins revealed different binding capabilities in the test used here.
The complexes formed by the supramolecular dye Congo red with myeloma immunoglobulins differ in stability. Those of high stability indicate the abnormal protein structure thought to produce clinical symptoms. This work proposes an easy technique to differentiate the stability of complexes.
骨髓瘤衍生免疫球蛋白常见的结构偏差会影响多肽链的堆积和结构域稳定性，增强其聚集倾向，并带来所有相关临床后果。本研究提出用刚果红与骨髓瘤免疫球蛋白复合作为一种通用测试，以揭示这些蛋白质的不稳定性。如果允许刚果红的大的带状超分子配体与蛋白质的β构象多肽链主干界面接触，它们就会与蛋白质形成复合物。骨髓瘤衍生的免疫球蛋白存在多肽链堆积缺陷时就会出现这种情况。
材料/方法：采用专门改良的血清蛋白二维琼脂糖电泳，该方法能在迁移过程中使刚果红与血清蛋白短暂接触，以揭示易于被配体渗透和结合的蛋白质成分的存在。电泳与刚果红与蛋白质的结合相结合，可以去除松散附着的染料，并直接在血清中评估免疫球蛋白组分的有效复合特性。
对与刚果红具有不同反应性的两条轻链的染料复合进行的比较研究证实，在所用条件下，染料结合取决于蛋白质的不稳定性。骨髓瘤蛋白在此处使用的测试中显示出不同的结合能力。
超分子染料刚果红与骨髓瘤免疫球蛋白形成的复合物稳定性不同。高稳定性的复合物表明存在被认为会产生临床症状的异常蛋白质结构。本研究提出了一种区分复合物稳定性的简便技术。
