Manjunath Kavyashree, Jeyakanthan Jeyaraman, Nakagawa Noriko, Shinkai Akeo, Yoshimura Masato, Kuramitsu Seiki, Yokoyama Shigeyuki, Sekar Kanagaraj
Supercomputer Education and Research Centre, Indian Institute of Science, Bangalore 560 012, India.
Acta Crystallogr Sect F Struct Biol Cryst Commun. 2010 Feb 1;66(Pt 2):180-3. doi: 10.1107/S1744309109052026. Epub 2010 Jan 28.
The study of proteins involved in de novo biosynthesis of purine nucleotides is central in the development of antibiotics and anticancer drugs. In view of this, a protein from the hyperthermophile Pyrococcus horikoshii OT3 was isolated, purified and crystallized using the microbatch method. Its primary structure was found to be similar to that of SAICAR synthetase, which catalyses the seventh step of de novo purine biosynthesis. A diffraction-quality crystal was obtained using Hampton Research Crystal Screen II condition No. 34, consisting of 0.05 M cadmium sulfate hydrate, 0.1 M HEPES buffer pH 7.5 and 1.0 M sodium acetate trihydrate, with 40%(v/v) 1,4-butanediol as an additive. The crystal belonged to space group P3(1), with unit-cell parameters a = b = 95.62, c = 149.13 A. Assuming the presence of a hexamer in the asymmetric unit resulted in a Matthews coefficient (V(M)) of 2.3 A(3) Da(-1), corresponding to a solvent content of about 46%. A detailed study of this protein will yield insights into structural stability at high temperatures and should be highly relevant to the development of antibiotics and anticancer drugs targeting the biosynthesis of purine nucleotides.
对参与嘌呤核苷酸从头生物合成的蛋白质的研究是抗生素和抗癌药物研发的核心。鉴于此，从嗜热栖热菌OT3中分离、纯化并使用微量分批法结晶了一种蛋白质。发现其一级结构与SAICAR合成酶相似，SAICAR合成酶催化嘌呤从头生物合成的第七步。使用Hampton Research Crystal Screen II条件34获得了衍射质量的晶体，该条件由0.05 M水合硫酸镉、0.1 M HEPES缓冲液pH 7.5和1.0 M三水合醋酸钠组成，并添加40%（v/v）1,4-丁二醇作为添加剂。该晶体属于空间群P3(1)，晶胞参数a = b = 95.62，c = 149.13 Å。假设不对称单元中存在六聚体，得到的马修斯系数（V(M)）为2.3 ų Da⁻¹，对应于约46%的溶剂含量。对这种蛋白质的详细研究将有助于深入了解高温下的结构稳定性，并且应该与针对嘌呤核苷酸生物合成的抗生素和抗癌药物的开发高度相关。
