There is described an apparatus for measuring protein characteristics comprising an X-ray fluorescence (XRF) spectrometer comprising a source of polychromatic X-rays, an X-ray detector, a protein, a molecule that has been exposed to and at least weakly binds to the protein, a plurality of X-ray fluorescence signal data obtained by irradiating chemical elements in the protein and molecule with the polychromatic X-rays and a security system for maintaining records for the data from the plurality of X-ray fluorescence signal measurements. There is also described an x-ray microscope for measuring a sample.
描述了一种测量蛋白质特性的仪器,该仪器包括一个 X 射线荧光 (XRF) 光谱仪,其中包括一个多色 X 射线源、一个 X 射线探测器、一个蛋白质、一个已暴露于该蛋白质并至少与该蛋白质弱结合的分子、通过用多色 X 射线照射蛋白质和分子中的化学元素而获得的多个 X 射线荧光信号数据,以及一个用于维护多个 X 射线荧光信号测量数据记录的安全系统。此外,还介绍了一种用于测量样品的 X 射线显微镜。
A Formal [3 + 3] Cycloaddition Reaction. 5. An Enantioselective Intramolecular Formal Aza-[3 + 3] Cycloaddition Reaction Promoted by Chiral Amine Salts
作者:Aleksey I. Gerasyuto、Richard P. Hsung、Nadiya Sydorenko、Brian Slafer
DOI:10.1021/jo050171s
日期:2005.5.1
A detailed account on chiral secondary amine salt promoted enantioselective intramolecular formal aza-[3 + 3] cycloadditions is described here for the first time. The dependence of enantioselectivity on the structural feature of these chiral amines is thoroughly investigated. This study also reveals a very interesting reversal of the stereochemistry in the respective cycloadducts obtained using C-1- and C-2-symmetric amine salts. In addition, the influence of solvents, counteranions, and temperatures on the enantioselectivity is described, and a unified mechanistic model based on experimental results as well as semiempirical calculations is proposed.