All three surface tryptophans in Type IIa cellulose binding domains play a pivotal role in binding both soluble and insoluble ligands

FEBS Letters

Nagy, Tibor³  Orosz, Laszlo⁴  Hazlewood, Geoffrey P.¹  Simpson, Peter²  Gilbert, Harry J.³  Williamson, Michael P.² 

[1] Laboratory of Molecular Enzymology, The Babraham Institute, Babraham, Cambridge CB2 4AT, UK;Department of Molecular Biology and Biotechnology, Krebs Institute, University of Sheffield, Sheffield S10 2TN, UK;Department of Biological and Nutritional Sciences, University of Newcastle upon Tyne, Newcastle upon Tyne NE1 7RU, UK;Institute for Molecular Genetics, Agricultural Biotechnology Center, P.O. Box 411, Godollo H-2101, Hungary

关键词: Cellulose binding domain;    Tryptophan mutant;    Xylanase A;    Pseudomonas fluorescens;   

DOI  :  10.1016/S0014-5793(98)00625-5

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The three surface tryptophans of the Type IIa cellulose binding domain of Pseudomonas fluorescens subsp. cellulosa xylanase A (CBD_XYLA) were independently mutated to alanine, to create the mutants W13A, W49A and W66A. The three mutant proteins were purified, and their capacity to bind to a variety of ligands was determined. The mutant proteins have native-like structures but exhibited much weaker affinity for crystalline and amorphous cellulose and for cellohexaose than the wild type. These data indicate that all three tryptophans are important for binding to cellulose, and support a model in which the three tryptophans form an aromatic strip on the surface of the protein that binds to a single cellulose.

【 授权许可】

Unknown