TIME RESOLVED XRAY DIFFRACT: ULTRATHIN LANGMUIR BLODGETT & SARCOPLASMIC RETICUL

骨骼肌浆网(SR)的钙-三磷酸腺苷酶 心肌是一种典型的依赖能量的离子运输 ATPase。我们正在试图澄清分子的细节 钙离子能量依赖性转运的机制 离子的时间分辨共振和非共振衍射 水合组织中钙离子-三磷酸腺苷酶谱结构的研究 分离的肌浆网和肌浆网定向多层 洗涤剂增溶的矢量取向单层膜 Ca2+-ATPase。使用弯曲磁力源的早期实验 NSL被限制在400毫秒以上的时间尺度内。 BioCAT的初始时间分辨研究双重点 APS/ANL的波荡器-磁光束线专注于确定 在仍提供以下数据的情况下可以记录的最小时间范围 统计准确率高。串联的最短持续时间 快门为5毫秒。全部可用的熔剂饱和了一台富士 5毫秒曝光的影像版。X射线衍射图 统计质量好的数据从超薄记录下来 衰减束流的Langmuir-Blodgett(LB)多层膜 强度提高了100倍。这些测试表明， 足够的流量来记录50微秒的曝光 可用通量。随后的研究使用了16通道的原型 可记录的多元素探测器(MED) 持续时间为16微秒、150纳秒的连续时间帧 帧之间的盲区时间。探测器的能力是 通过记录1024个连续的15个时间帧来演示 毫秒的持续时间形成了一个2-双层的CD-花生四酸LB-膜。 用Ca~(2+)-ATPase记录了时间分辨的X-射线衍射数据 连续时间帧中的多层-持续时间为150毫秒。 笼状三磷酸腺苷的闪光光解被用于同步系综。

The Ca2+-ATPase of the sarcoplasmic reticulum (SR) in skeletal and cardiac muscle is a prototypical energy-dependent ion transport ATPase. We are seeking to elucidate the details of the molecular mechanism responsible for the energy-dependent transport of calcium ions using time resolved resonance and non-resonance diffraction studies of the profile structure of the Ca2+-ATPase within hydrated oriented multilayers of isolated sarcoplasmic reticulum and vectorially-oriented single monolayers of the detergent-solubilized Ca2+-ATPase. Early experiments using bending magnet sources at the NSLS were limited to time scales of longer than 400 milliseconds. Initial time-resolved studies at the BioCAT doubly-focused undulator-magnet beamline at the APS/ANL focused on determining the minimum time-frame that could be recorded while still provide data of high statistical accuracy. The minimum duration of the in-line shutter was 5 milliseconds. The full available flux saturated a FUJI Image Plate in a 5 millisecond exposure. X-ray diffraction patterns of good statistical quality were recorded from ultra-thin Langmuir-Blodgett (LB) multilayers films by attenuating the beam intensity by 100-fold. These tests indicated that there was sufficient flux to record 50 microsecond exposures using the full available flux. Subsequent studies used the 16-channel prototype of the Multi-Element Detector (MED) which is capable of recording contiguous time frames of 16 microseconds duration with 150 nanosecond blind time between frames. The detectors capabilities were demonstrated by recording 1024 contiguous time-frames of 15 millisecond duration form a 2-bilayer Cd-Arachidate LB-flim. Time-resolved x-ray diffraction data were recorded from Ca2+-ATPase multilayers in contiguous time-frames of 150 millisecond duration. Flash photolysis of caged-ATP was used to synchronize the ensemble.