Ab initio structure determination and functional characterization of CBM36: A new family of calcium-dependent carbohydrate binding modules
Ab initio structure determination and functional characterization of CBM36: A new family of calcium-dependent carbohydrate binding modules
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DOI：
10.1016/j.str.2004.04.022
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发表时间：
2004-07-01
期刊：
影响因子：
5.7
通讯作者：
Davies, GJ
中科院分区：
文献类型：
--
作者：
Jamal-Talabani, S;Boraston, AB;Davies, GJ
多糖的酶降解利用多模酶，其碳水化合物结合模块(CBM)将催化区域定位于顽固的底物上。在这里，我们报道了多粘类芽孢杆菌木聚糖酶43A的CBM36结构域的从头算结构测定和随后在0.8埃分辨率下的精制。亲和电泳法、等温滴定量热法和紫外差示光谱分析表明，CBM36是一个新的呼唤依赖的木聚糖结合结构域。在1.5埃分辨率下，CBM36与木三糖和钙离子的络合物的三维结构与天然结构相比显示出显著的构象变化，揭示了其独特的钙依赖的木寡糖结合的分子基础--O2和O3羟基的配位。CBM36是一种新兴的碳水化合物结合模块，它越来越多地在工业上得到应用，并在绘制植物细胞的“糖结构”方面显示出巨大的潜力。
The enzymatic degradation of polysaccharides harnesses multimodular enzymes whose carbohydrate binding modules (CBM) target the catalytic domain onto the recalcitrant substrate. Here we report the ab initio structure determination and subsequent refinement, at 0.8 Angstrom resolution, of the CBM36 domain of the Paenibacillus polymyxa xylanase 43A. Affinity electrophoresis, isothermal titration calorimetry, and UV difference spectroscopy demonstrate that CBM36 is a novel Call-dependent xylan binding domain. The 3D structure of CBM36 in complex with xylotriose and Ca2+, at 1.5 Angstrom resolution, displays significant conformational changes compared to the native structure and reveals the molecular basis for its unique Ca2+-dependent binding of xylooligosaccharides through coordination of the O2 and O3 hydroxyls. CBM36 is one of an emerging spectrum of carbohydrate binding modules that increasingly find applications in industry and display great potential for mapping the "glyco-architecture" of plant cells.