Rajaram Venkatesan, Rajaganapathi Jagannathan, Khan Farida, Savithri Handanahal S, Murthy Mathur R N
Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India.
Acta Crystallogr D Biol Crystallogr. 2003 Sep;59(Pt 9):1668-9. doi: 10.1107/s0907444903015476. Epub 2003 Aug 19.
Diaminopropionate (DAP) ammonia lyase (a PLP-dependent enzyme; EC 4.3.1.15) catalyzes the alpha,beta-elimination reaction of both L- and D-alpha,beta-diaminopropionate to form pyruvate and ammonia. Escherichia coli DAP ammonia lyase gene was cloned and overexpressed in E. coli and the protein was purified to homogeneity and crystallized using the hanging-drop vapour-diffusion technique. Crystals of two different morphologies were obtained, one of which belonged to the tetragonal space group P4(1)2(1)2 (or P4(3)2(1)2), with unit-cell parameters a = b = 86.01, c = 209.56 A, and the other to the monoclinic space group P2(1), with unit-cell parameters a = 87.78, b = 94.35, c = 96.02 A, beta = 109.73 degrees. The tetragonal crystals diffracted X-rays to 3.0 A resolution, while diffraction from the monoclinic form extended to 2.5 A. Complete X-ray diffraction data sets have been collected for both crystal forms.
二氨基丙酸（DAP）氨裂解酶（一种依赖磷酸吡哆醛的酶；EC 4.3.1.15）催化L-和D-α,β-二氨基丙酸的α,β-消除反应，生成丙酮酸和氨。大肠杆菌DAP氨裂解酶基因被克隆并在大肠杆菌中过表达，该蛋白被纯化至同质，并采用悬滴气相扩散技术进行结晶。获得了两种不同形态的晶体，其中一种属于四方晶系空间群P4(1)2(1)2（或P4(3)2(1)2），晶胞参数a = b = 86.01，c = 209.56 Å，另一种属于单斜晶系空间群P2(1)，晶胞参数a = 87.78，b = 94.35，c = 96.02 Å，β = 109.73°。四方晶体的X射线衍射分辨率为3.0 Å，而单斜晶型的衍射扩展至2.5 Å。已收集了两种晶体形式的完整X射线衍射数据集。
