Chang Chin Yuan, Hsieh Yin Cheng, Wang Ting Yi, Chen Chun Jung, Wu Tung Kung
Department of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan.
Acta Crystallogr Sect F Struct Biol Cryst Commun. 2009 Mar 1;65(Pt 3):216-8. doi: 10.1107/S174430910900092X. Epub 2009 Feb 12.
The aminoacylhistidine dipeptidase (PepD) protein encoded by Vibrio alginolyticus pepD was successfully overexpressed and characterized and the putative active-site residues responsible for metal binding and catalysis were identified. The purified enzyme contained two zinc ions per monomer. The recombinant dipeptidase enzyme, which was identified as a homodimer in solution, exhibited broad substrate specificity for Xaa-His dipeptides, with highest activity towards the His-His dipeptide. The purified protein was crystallized using the hanging-drop vapour-diffusion method. Preliminary crystallographic analysis showed that the crystal belonged to space group P6(1) or P6(5), with unit-cell parameters a = b = 80.42, c = 303.11 A. The crystal contained two molecules per asymmetric unit and the predicted solvent content was 53.4%.
由溶藻弧菌pepD编码的氨酰基组氨酸二肽酶（PepD）蛋白成功实现了过表达和特性鉴定，并确定了负责金属结合和催化的假定活性位点残基。纯化后的酶每个单体含有两个锌离子。重组二肽酶在溶液中被鉴定为同型二聚体，对Xaa-His二肽表现出广泛的底物特异性，对His-His二肽的活性最高。采用悬滴气相扩散法对纯化后的蛋白进行结晶。初步晶体学分析表明，该晶体属于空间群P6(1)或P6(5)，晶胞参数a = b = 80.42，c = 303.11 Å。每个不对称单元的晶体包含两个分子，预测溶剂含量为53.4%。
