Kulkarni K A, Srivastava A, Mitra N, Sharon N, Surolia A, Vijayan M, Suguna K
Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India.
Proteins. 2004 Sep 1;56(4):821-7. doi: 10.1002/prot.20168.
The three-dimensional structure of the recombinant form of Erythrina corallodendron lectin, complexed with lactose, has been elucidated by X-ray crystallography at 2.55 A resolution. Comparison of this non-glycosylated structure with that of the native glycosylated lectin reveals that the tertiary and quaternary structures are identical in the two forms, with local changes observed at one of the glycosylation sites (Asn17). These changes take place in such a way that hydrogen bonds with the neighboring protein molecules in rECorL compensate those made by the glycan with the protein in ECorL. Contrary to an earlier report, this study demonstrates that the glycan attached to the lectin does not influence the oligomeric state of the lectin. Identical interactions between the lectin and the non-covalently bound lactose in the two forms indicate, in line with earlier reports, that glycosylation does not affect the carbohydrate specificity of the lectin. The present study, the first of its kind involving a glycosylated protein with a well-defined glycan and the corresponding deglycosylated form, provides insights into the structural aspects of protein glycosylation.
刺桐凝集素重组形式与乳糖复合后的三维结构已通过X射线晶体学在2.55埃分辨率下得以阐明。将这种非糖基化结构与天然糖基化凝集素的结构进行比较，结果显示两种形式的三级和四级结构相同，仅在一个糖基化位点（Asn17）观察到局部变化。这些变化以这样一种方式发生，即重组刺桐凝集素（rECorL）中与相邻蛋白质分子形成的氢键补偿了刺桐凝集素（ECorL）中聚糖与蛋白质形成的氢键。与早期报告相反，本研究表明附着在凝集素上的聚糖不会影响凝集素的寡聚状态。两种形式中凝集素与非共价结合乳糖之间相同的相互作用，与早期报告一致，表明糖基化不会影响凝集素的碳水化合物特异性。本研究是同类研究中的首例，涉及一种具有明确聚糖的糖基化蛋白质及其相应的去糖基化形式，为蛋白质糖基化的结构方面提供了见解。
