Brink J, Chiu W
Verna and Marrs McLean Department of Biochemistry, Baylor College of Medicine, Houston, Texas 77030.
J Struct Biol. 1994 Jul-Aug;113(1):23-34. doi: 10.1006/jsbi.1994.1029.
A Gatan 1024 x 1024 slow-scan charge-coupled device (CCD) camera has been interfaced to a JEOL4000EX electron cryomicroscope and explored for its usefulness in the electron crystallographic analysis of thin, glucose-embedded crystals of crotoxin complex kept at -125 degrees C. We show that the camera allows for an on-line assessment of the crystals' crystallinity, flatness, and thickness. Intensities obtained from electron diffraction patterns acquired with the camera have been statistically analyzed and were found to be consistent with theoretically expected values. A quantitative analysis of the diffraction intensity as function of the accumulated electron dose suggests the possibility of recording up to 250 diffraction patterns with 3.5 A resolution from a single crotoxin complex crystal 128 A thick. Tilt series of 125 electron diffraction patterns with 3.5 A data acquired from a single crystal are shown to be practically feasible. The current study demonstrates for the first time the effectiveness of using a slow-scan CCD camera for electron diffraction data collection from thin protein crystals at near atomic resolution.
一台Gatan 1024×1024慢扫描电荷耦合器件（CCD）相机已与一台JEOL4000EX电子低温显微镜连接，并对其在电子晶体学分析保存在-125℃的薄的、葡萄糖包埋的巴曲毒素复合物晶体中的用途进行了探索。我们表明，该相机可对晶体的结晶度、平整度和厚度进行在线评估。对用该相机获取的电子衍射图的强度进行了统计分析，发现与理论预期值一致。对衍射强度作为累积电子剂量函数的定量分析表明，有可能从一块128埃厚的单个巴曲毒素复合物晶体中以3.5埃分辨率记录多达250个衍射图。从单个晶体获取的具有3.5埃数据的125个电子衍射图的倾斜系列显示在实际中是可行的。当前研究首次证明了使用慢扫描CCD相机从近原子分辨率的薄蛋白质晶体收集电子衍射数据的有效性。
