Mechanism of binding of mono- and oligosaccharides to concanavalin A: a solvent proton magnetic relaxation dispersion.
Mechanism of binding of mono- and oligosaccharides to concanavalin A: a solvent proton magnetic relaxation dispersion.
复制标题
单糖和寡糖与刀豆球蛋白 A 结合的机制：溶剂质子磁弛豫分散体。
DOI：
10.1021/bi00579a019
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发表时间：
1979
期刊：
影响因子：
2.9
通讯作者：
R. Brown
中科院分区：
文献类型：
--
作者：
C. Brewer;R. Brown
Curtis F. Brewer*和Rodney D. Brown， III摘要：在以前的研究中，通过观察溶剂水质子在宽磁场范围内的自旋晶格弛豫率（re1）的磁场依赖（色散），研究了锰-锰蛋白A （Ca2+-Mn2+-Con A）中溶剂水分子与Mn2+离子的相互作用[Koenig， S. H., Brown， RD, & Brewer， C. F.(1973) Proc. Natl。学会科学。[USA 70,475]，我们已经证明7f*是由交换水配体在Mn2+离子上的停留时间决定的。在Ca2+- mn2 +- con - A溶液中进行了额外的测量，在足够量的甲基A -或ß-D-glucopyranoside的存在下，使蛋白质的碳水化合物结合位点饱和，并且观察到整个色散谱的松弛率降低了约15%。在本研究中，我们测量了一系列单糖和寡糖与Ca2+- mn2 +- con a结合对溶剂水质子弛豫率的影响，磁场范围从5 Oe到12 Oe。所观察到的松弛速率变化对所测试的糖类的亲和常数很敏感，因为这种影响与与蛋白质结合的糖类的数量成正比。定量分析表明，在糖结合时溶剂弛豫速率的降低是由于Mn2+离子交换水配体的停留时间的增加。这种效应与糖结合后蛋白质的构象变化是一致的。我们发现甲基a-和3- d -葡萄糖吡喃苷，methyl-D-mannópyranoside和碘苯基3- d -葡萄糖吡喃苷的结合量足够饱和蛋白质的碳水化合物位点，会产生相同的交换水配体停留时间的增加。半乳糖和o-碘苯基3- d -半乳糖吡喃苷（o-碘苯基3- d -半乳糖吡喃苷）是一种从豆荚（Canavalia ensiformis）中分离出来的凝集素，它具有不同寻常的生物学特性。特别是，它与正常细胞和转化细胞表面结合的能力使其成为探索各种细胞表面相关生物效应的有力工具（cf. Lis & Sharon, 1973）。Con A与细胞膜的相互作用与蛋白质的糖结合特性有关。Goldstein等人（1965）已经证明Con A的糖结合特异性是针对葡萄糖和甘露糖的单糖，它们在3、4和6位上含有相似的羟基构型。的
Curtis F. Brewer* and Rodney D. Brown, III abstract: In previousstudies of the interaction of solvent water molecules with the Mn2+ ion in manganese-concanavalin A (Ca2+-Mn2+-Con A) by observation of the magnetic field dependence (dispersion) of the spin-lattice relaxationrate (re1) of the solvent water protons over a wide range of magnetic fields [Koenig, S. H., Brown, RD, & Brewer, C. F.(1973) Proc. Natl. Acad. Sci. USA 70, 475], we have shown that 7f* is dominated by the residence time of an exchanging water ligand (s) on the Mn2+ ion. Additional measurements were made on Ca2+-Mn2+-Con A solutions in the presence of sufficient amounts of either methyl a- or, ß-D-glucopyranoside to saturate the carbohydrate binding sites of the protein, and it was observed that the relaxation rate across the dispersion spectrum was reduced by approximately 15%. In thepresent study, we have measured the effects of binding of a series of mono- and oligosaccharides to Ca2+-Mn2+-Con A on the solvent water proton relaxation rate over a range of magnetic fields from 5 Oe to 12 KOe. The observed change in relaxation rate was shown to be sensitive to the affinity constants of the saccharides tested in that the effect was proportional to the amount of saccharide bound to the protein. Quantitative analysis revealed that theobserved decrease in solvent relaxation rate upon saccharide binding is due to an increase in the residence time of the exchanging water ligand (s) of the Mn2+ ion. This effect is consistent with a conformational change in the protein upon binding of saccharides. We find that binding of methyl a- and 3-D-glucopyranoside, methyl-D-mannópyranoside, and oiodo-phenyl 3-D-glucopyranoside in sufficient amountsto saturate the carbohydrate sites of the protein produces the same in-crease in the residence time of the exchanging water ligand (s). Galactose and o-iodophenyl 3-D-galactopyranoside, which doInterest in the protein concanavalin A (Con A), 1 a lectin isolated from the jack bean (Canavalia ensiformis), derives from its unusual biological properties. In particular, its ability to bind to the surface of both normal and transformed cells has made it a powerful tool for exploring a wide variety of cell-surface related biological effects (cf. Lis & Sharon, 1973). The interaction of Con A with cell-surface membranes is related to the saccharide binding properties of the protein. The saccharide binding specificity of Con A has been shownby Goldstein et al.(1965) to be directed toward the mono-saccharides glucose and mannose, which contain similar hydroxyl group configuration atthe 3, 4, and 6 positions. The