MOLECULAR DYNAMICS AND VIBRATIONAL CHARACTERISTICS OF MEMBRANE ASSEMBLIES

工作总结：我们的研究工作 包括两个一般领域：（A）的调节作用 双层脂质对膜结构重组的影响 蛋白质，和（B）仪器开发和应用 振动拉曼和红外光谱成像技术。 (A)我们的兴趣在于描述脂质波动的影响 生物膜内的微区最近集中在簇 在由脂质单分子或多分子组成的双层基质内形成， 多不饱和Sn-2链和饱和Sn-1链组装体。的 这些脂质微聚集体的侧向可压缩性 有效地对诱导的 整合膜内发生的构象变化 proteins.在研究光谱特异性脂质双层时， 适当的酰基链氘代允许振动动力学 每一个链的部分，以分别监测。拉曼和 红外光谱技术应用于检查 双层系列包括 1-二十烷酰基（d39）-2-二十烯酰基-sn-甘油-3-磷酸胆碱 [C（20-d39）：C（20：1 delta j）PC，其中j=5、8、11和13]。建立 与每个链系统相关的有序/无序参数是 作为不饱和链位置的函数进行评估 双键多晶样品和含水双层 检查分散体。各种计算技术 提供了链簇大小的估计，其在3-19之间变化 这一系列磷脂的酰基链。例如，最大的 sn-1链结构域，特异性来源于货车范德华 相邻分子链之间的相互作用， 对于C（20-d39）：C（20：15）PC种类。使用这些光谱 方法，我们已经详细研究了微异质性， 各种双层组件。（B）重点放在 增强中红外光谱化学成像 显微镜技术相结合的步进扫描干涉测量与 红外敏感二维焦平面阵列 探测器高性能数字成像与 非侵入性的高分辨率光学光谱学允许 不同化学物种空间分布的可视化 在各种主机环境中。这项技术的力量在于 也表现在同时获取红外线 每个空间位置的光谱。作为效用的一个例子 在诊断病理学的技术，我们应用红外线 小鼠小脑组织的影像学研究 展示了C型尼曼匹克的形态和病理 疾病红外图像提供了定性的描述， 未染色的患病组织和 对照动物。吸收率图像，连同它们的相关 光谱，允许组织内的各种细胞层， 鉴定对反映以下特征的单个光谱进行统计分析： 不同的细胞层提供了简明的定量描述， 观察到的生化变化。

Summary of Work: Our research efforts encompassed two general areas: (A) The modulatory effects of bilayer lipids on the structural reorganizations of integral membrane proteins, and (B) the instrumental development and applications of vibrational Raman and infrared spectroscopic imaging techniques. (A) Our interest in characterizing the effects of fluctuating lipid microdomains within biomembranes has recently focused on cluster formation within bilayer matrices comprised of lipid mono- or polyunsaturated sn-2 chain and saturated sn-1 chain assemblies. The lateral compressibility properties of these lipid microaggregates are effective in exerting a modulatory influence on induced conformational changes occurring within integral membrane proteins. In studying spectroscopically specific lipid bilayers, appropriate acyl chain deuteration allows the vibrational dynamics of each chain moiety to be monitored separately. Both Raman and infrared spectroscopic techniques were applied toward examining the bilayer series comprised of 1-eicosanoyl(d39)-2-eicosenoyl-sn-glycero-3-phosphocholine [C(20-d39):C(20:1 delta j)PC, with j=5, 8, 11, and 13]. Established order/disorder parameters pertinent to each chain system were assessed as a function of the placement of the unsaturated chain double bond. Both polycrystalline samples and aqueous bilayer dispersions were examined. Various computational techniques provided estimates of chain cluster sizes, which vary between 3-19 acyl chains for this series of phospholipids. For example, the largest sn-1 chain domain, originating specifically from van der Waals interactions between the chains of neighboring molecules, occurs for the C(20-d39):C(20:1 5)PC species. Using these spectroscopic approaches, we have examined in detail the microheterogeneity of a variety of bilayer assemblies. (B)Emphasis has been placed on enhancing our mid-infrared spectroscopic chemical imaging microscopy techniques by combining step-scan interferometry with state-of-the-art infrared senstive two-dimensional focal plane array detectors. The integration of high performance digital imaging with noninvasive, high resolution optical spectroscopy allows a visualization of the spatial distribution of distinct chemical species in a variety of host environments. The power of the technique is also manifest in the simultaneous acquisition of an infrared spectrum for each spatial location. As an example of the utility of the technique in diagnostic pathology, we applied the infrared imaging methodology to a study of cerebellar tissue from mice presenting the morphology and pathology of Niemann-Pick type C disease. The infrared images provided qualitative descriptions of the biochemical differences between unstained tissue from diseased and control animals. The absorbance images, together with their related spectra, allowed the various cellular layers within the tissue to be identified. Statistical analyses of the individual spectra reflecting the various cellular layers provided concise quantitative descriptions of the observed biochemical variations.