Episodic positive selection during the evolution of naphthalene dioxygenase to nitroarene dioxygenase

作者：Dutta Arindam; Chakraborty Joydeep; Dutta Tapan K^*

来源：Biochemical and Biophysical Research Communications, 2013, 440(1): 68-75.

DOI：10.1016/j.bbrc.2013.09.029

• Aromatic ring-hydroxylating oxygenase
• Naphthalene dioxygenase
• Nitroarene dioxygenase
• Adaptive evolution
• Episodic positive selection

Using different maximum-likelihood models of adaptive evolution, signatures of natural selective pressure, operating across the naphthalene family of dioxygenases, were examined. A lineage- and branch-site specific combined analysis revealed that purifying selection pressure dominated the evolutionary history of the enzyme family. Specifically, episodic positive Darwinian selection pressure, affecting only a few sites in a subset of lineages, was found to be responsible for the evolution of nitroarene dioxygenases (NArDO) from naphthalene dioxygenase (NDO). Site-specific analysis confirmed the absence of diversifying selection pressure at any particular site. Different sets of positively selected residues, obtained from branch-site specific analysis, were detected for the evolution of each NArDO. They were mainly located around the active site, the catalytic pocket and their adjacent regions, when mapped onto the 3D structure of the alpha-subunit of NDO. The present analysis enriches the current understanding of adaptive evolution and also broadens the scope for rational alteration of substrate specificity of enzyme by directed evolution.

• 出版日期2013-10-11
• 单位常州工学院