OLIGOMERIZATION STATE OF THE MONOAMINE OXIDASES

这个子项目是利用资源的许多研究子项目之一。 由NIH/NCRR资助的中心拨款提供。对子项目的主要支持 子项目的首席调查员可能是由其他来源提供的， 包括美国国立卫生研究院的其他来源。为子项目列出的总成本可能 表示该子项目使用的中心基础设施的估计数量， 不是由NCRR赠款提供给次级项目或次级项目工作人员的直接资金。 单胺氧化酶(A和B)是线粒体膜外结合酶，在胺类神经递质代谢中发挥重要作用。序列和模型研究表明，人类MAO A与所有其他哺乳动物MAO A的不同之处在于，由于Glu151Lys突变，它在外膜上是单体的，而不是二聚体。纯化的人和大鼠MAO A的晶体结构为这一假说提供了额外的支持。为了提供直接的实验测试，将合成在对位带有氮氧自旋标记的抑制剂pargyline的类似物，并将其共价结合到人和大鼠MAO A、人MAO A的Lys151Glu突变体和人MAO B的活性部位。人MAO B的二聚体结构数据表明，活性部位空腔之间的距离为42？这个距离很容易通过对这些样品的双量子相干EPR测量来确定。偶极光谱数据将提供距离信息，以确定这些酶在线粒体外膜中是以二聚体形式还是以单体形式存在。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Monoamine oxidases ( A & B) are outer mitochondrial membrane-bound enzymes that play important roles in amine neurotransmitter metabolism. Sequence and modeling studies suggest human MAO A differs from all other mammalian MAO A in that it is monomeric rather than dimeric in the outer membrane due to a Glu151Lys mutation. Crystal structures of purified human and rat MAO A provide additional support for this hypothesis. To provide a direct experimental test, analogues of the inhibitor pargyline with a nitroxide spin label on the para position will be synthesized and covalently incorporated into the active sites of human and rat MAO A, the Lys151Glu mutant of human MAO A, and human MAO B. Structural data of the dimeric form of crystalline human MAO B show the distance between the active site cavities is 42 ¿. This distance is readily determined by Double Quantum Coherence EPR measurements on these samples. The dipolar spectral data will provide distance information that will determine if these enzyme species are in their dimeric or monomeric forms in the mitochondrial outer membrane.