STRUCTURAL STUDY OF ARABIDOPSIS CAD5 (CINNAMYL ALCOHOL DEHYDROGENASE 5) ENZYME

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 木质素、木脂素和异黄酮类化合物是苯丙烷类化合物中非常重要的一类。它们在植物防御中发挥重要作用，帮助寄主区分生物病原体和共生非病原体。更重要的是，苯丙烷途径的各种最终代谢产物具有重要的药理作用，特别是在癌症预防方面。尽管这些化合物在植物生物学和人类健康中很重要，但对所涉及的酶还没有进行系统的研究。我们研究了苯丙烷生物合成途径中最重要的酶之一。肉桂醇脱氢酶5(CAD5)是一类依赖NADPH的酶，催化各种苯基丙烯醛衍生物的还原。一般来说，该反应生成几种单木脂醇，后者主要是木脂素的前体。我们已经用旋转阳极(Rigaku，Raxis-IV)获得了分辨率为2.5？的CAD5晶体(P41212)的衍射数据。然而，我们无法进行分子置换，因为没有任何类似的蛋白质被解决。因此，必须使用MAD。除了MAD数据，高分辨率数据和复杂晶体(AtCAD5-辅因子/底物/产物)的衍射数据对于研究其独特的立体特异性转化AtCAD5的确切机制是绝对必要的。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Lignins, lignans and isoflavonoids represent very important class of phenylpropanoids. They play important roles in plant defense, helping hosts discriminate between biological pathogens and symbiotic non-pathogens. More importantly, various final metabolic products of phenylpropanoid pathway have important pharmacological roles, especially in cancer prevention. Despite the importance of these compounds in plant biology and in human health, systematic studies on the enzymes involved have not been done. We have studied one of the most important enzymes involved in phenylpropanoid biosynthesis pathways. Cinnamyl alcohol Dehydrogenase 5 (CAD5) enzyme depicts a class of NADPH-dependent enzymes catalyzing the reduction of various phenylpropenyl aldehyde derivatives. Generically, this reaction makes several monolignols, with the latter mainly being precursors of lignans. We have already obtained the diffraction data of CAD5 crystal (P41212) with 2.5 ¿ resolutions using a rotating anode (Rigaku, Raxis-IV). However, we couldn't perform the molecular replacement because there is no any similar protein solved. Therefore, MAD must be used. In addition to MAD data, the high resolution data and complex crystal (AtCAD5-cofactor/substrate/product) diffraction data are absolutely required for the studying of the exact mechanism of its unique stereospecific conversion of AtCAD5.