福氏志贺菌硫氧还过氧化物酶的晶体生长和初步晶体学研究（英文）

Crystallization and Preliminary Crystallographic Analysis of Thioredoxin-dependent Thiol Peroxidase(SF2523) From Shigella flexneri 2a str.301

过氧化物酶是一类广泛存在于生物体内的抗氧化剂,清除有氧代谢过程中产生的活性氧,对于保护机体内的生物大分子有重要的生物学功能.福氏志贺菌硫氧还过氧化物酶(SF2523)作为过氧化物酶家族的一员,通过清除福氏志贺菌体内的活性氧,在维持其活性和致病性上起重要作用.目前,SF2523的三维结构还没有得到解析,其具体的功能机制也尚不清楚.为了得到SF2523蛋白的三维结构,进而了解具体的功能机制,实验获得了均一稳定的可溶蛋白,验证具有体外活性,培养出可用于X射线衍射的蛋白质晶体.在中国科学院高能物理研究所同步辐射装置收到晶体的衍射数据供结构解析使用.SF2523晶体属于空间群P2_12_12_1,晶胞参数为a=35.80,b=50.63,c=88.52,α=β=γ=90.00°,每个晶体学不对称单位含有1个蛋白质分子,马修斯系数为2.03~3/u,溶剂含量为39.56%.

Shigella flexneri was the most common pathogen causing bacillary dysentery. Thioredoxin-dependent thiol peroxidase （SF2523） proteins was from Shigellaflexneri 2a str. 301. It belonged to thioredoxin peroxidase family and played an important role in protecting the biological macromolecule by scavenging active oxygen generated in the process of aerobic metabolism. To understand the underlying mechanism, prokaryotically expressed thioredoxin-dependent thiol peroxidase protein was purified using affinity chromatography and gel filtration, crystallized using the vapour-diffusion method. The crystal grew in a condition consisting of 1.8 mol/L tri-Ammonium citrate, pH 7.0 using 1 g/L protein solution at 289 K. A complete data set was collected from a crystal to 2.75A resolution using synchrotron radiation at 100 K. The crystal belonged to space group P212121t, with unit-cell parameters a = 35.80 A, b = 50.63A, c = 88.52 A, α =β = γ = 90.00°. One molecule was found in the asymmetric unit with a Mat-thews coefficient of 2.03 A3/u, corresponding to a solvent content of 39.56%.