CRYSTAL STRUCTURE OF COLICIN IA DETERMINATION BY CRYOCRYSTALLOGRAPHY

使用1）快速冷冻和2）大幅面MAR成像板， 光束线7-1，分辨率已从以前的2.35 E扩展到 2.8E的极限。这个2.8E的数据集是从冷冻晶体中获得的 分辨率受到较小MAR成像板的限制。 冻结 消除了早期实验中的辐射损伤 一 广泛的低温溶剂和人工母液， 考察 用锂代替硫酸铵/柠檬酸盐缓冲液 硫酸盐/乙酸盐缓冲液是成功的。 这种人造母液 将用于重原子浸泡。 低分辨率筛选后 实验室中的数据，有希望的候选人将被带到SSRL。 迄今为止最好的候选者是CH 3 HgCl;单位点Cys突变体将 也可以使用（天然的没有半胱氨酸）。

Using 1) flash-freezing and 2) large-format MAR imaging plate at beamline 7-1, resolution has been extended to 2.35 E from previous limit of 2.8 E. This 2.8 E data set was obtained from frozen crystals with resolution limited by the smaller MAR imaging plates. Freezing has eliminated the radiation damage plaguing earlier experiments. A wide range of cryosolvents and artificial mother liquors were examined. Replacement of ammonium sulfate/citrate buffer by lithium sulfate/acetate buffer was successful. This artificial mother liquor will be used for heavy atom soaks. After screening low-resolution data in the lab, the promising candidates will be brought to SSRL. The best candidate to date is CH3HgCl; single-site Cys mutants will also be utilized (native has no cysteines).