Surface hydrophobic amino acid residues in cellulase molecules as a structural factor responsible for their high denim-washing performance
Surface hydrophobic amino acid residues in cellulase molecules as a structural factor responsible for their high denim-washing performance
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DOI：
10.1016/s0141-0229(00)00264-7
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发表时间：
2000-11-15
影响因子：
3.4
通讯作者：
Ankudimova, NV
中科院分区：
文献类型：
--
作者：
Gusakov, AV;Sinitsyn, AP;Ankudimova, NV
采用模型微量法比较了六种纯化的真菌纤维素酶（四种内切-1,4- β - d -葡聚糖酶和两种纤维素生物水解酶）对牛仔布的洗涤性能。每mg蛋白质中纤维素生物水解酶的性能远低于内切葡聚糖酶。对于内切葡聚糖酶，最佳和最差酶之间的差异高达5倍。将氨基酸固定在交联琼脂糖上的实验表明，由于疏水相互作用和氢键的形成，氨基酸侧链可能与靛蓝结合。结合效果最好的是Tyr和Phe。纤维素酶分子的三维结构分析表明，酶的洗涤性能与(i)蛋白质球表面暴露于溶剂的芳香残基的数量（百分比）或（ii）表面疏水残基的总百分比之间存在一定的相关性。所提供的数据证明，某些纤维素酶的分子表面具有疏水结构域（紧密排列的非极性残基簇），可能与靛蓝结合，从而起到乳化剂的作用，帮助染料从纤维素纤维中浮到体溶液中。(C) 2000 Elsevier Science Inc.；版权所有。
The denim-washing performance of six purified fungal cellulases (four endo-1,4-beta -D-glucanases and two cellobiohydrolases) was compared using a model microassay. The performance of cellobiohydrolases per mg of protein was much lower than that of endoglucanases. For endoglucanases, it varied up to 5 times between the best and the worst enzyme. Experiments with amino acids immobilized on cross-linked agarose showed that their side chains may bind indigo owing to hydrophobic interactions and formation of hydrogen bonds. The best binding effects provided Tyr and Phe. Analysis of three-dimensional structures of cellulase molecules showed that a certain correlation exists between the washing performance of enzyme and (i) quantity (percentage) of aromatic residues exposed to solvent on the surface of protein globule or (ii) overall percentage of the surface hydrophobic residues. Data presented provide an evidence that the molecules of certain cellulases, which have hydrophobic domains (clusters of closely located non-polar residues) on their surface, may bind indigo and thus act as emulsifiers helping the dye to float out of cellulose fibers to the bulk solution. (C) 2000 Elsevier Science Inc. All rights reserved.