QUINOENZYMES--BIOGENESIS STRUCTURE AND FUNCTION

在过去的五年中，一类新的蛋白质被描述出来， 指定的藜麦蛋白。这些含有辅因子的蛋白质 在它们的多肽骨架中，揭示了一种新的策略 生物中氧化还原辅因子的产生。利用以下组合 多方面的化学、生物化学和分子生物学方法 将继续对这些系统进行研究。对这一事件的详细调查 铜胺氧化酶中辅因子Topa-Quone的生物发生 (曹的)是有计划的，目标是了解CAO的情况 能够催化“自我加工”。到目前为止可用的数据 CAO的活性部位铜在辅因子生物发生和 催化周转率。虽然正式成为CAO家族的一员 蛋白质，赖氨酰氧化酶(LO)的不同之处在于它的尺寸更小， 缺乏显著的序列同源性。从这方面的初步数据 实验室表明，虽然LO包含一种五元结构，但这是 与以前在其他蛋白质中看到的结构不同。大号 计划进行一些实验，包括对活性的表征 位点衍生多肽及其模型的合成和比较研究 化合物。四种克隆和测序的真核生物的序列同源性 曹的表明了一个保守的结构基序，指向C-末端 蛋白质；这个结构基序包含两个TPQ共有序列 以及可能的组氨酸配基到铜。酵母胺基因 多态汉逊酵母的氧化酶(姚)将被修饰以表达 C-末端结构域，目的是确定辅因子 生物发生可以在这个领域内发生。目前正在进行的努力， 获得姚的X光结构将继续下去，并最终 延伸到姚的变异形式。解决方案研究，重点关注 胺氧化物酶来自牛血浆和姚，将解决一些问题 问题，包括活性位点共识序列在 确定底物专一性，活性部位碱基的性质 催化底物氧化，以及半脱氢酶的化学机理 将氧气还原为过氧化氢的反应。vt.给出 它们具有广泛的生理功能，包括氧化 生物胺从血液中的去除和交联剂 胶原蛋白和弹性蛋白是研究中的藜麦蛋白直接相关的 为人类健康干杯。

During the past five years a new class of proteins has been described, designated quinoproteins. These proteins, which contain their cofactor within their polypeptide backbone, reveal a novel strategy for the generation of redox cofactors in biology. Utilizing a combination of chemical, biochemical and molecular biological approaches, multifaceted studies of these systems will be pursued. A detailed investigation of the biogenesis of the cofactor topa quinone (TPQ) in the copper amine oxidases (CAO's) is planned, with the goal of understanding how the CAO's are capable of catalyzing "self processing". Data available thus far implicate the active site copper of CAO's in both cofactor biogenesis and catalytic turnover. Although formally a member of the CAO family of proteins, lysyl oxidase (LO) differs by virtue of its reduced size and lack of significant sequence homology. Preliminary data from this laboratory indicate that while LO contains a quino-structure, this is different from structures seen previously in other proteins. A large number of experiments are planned, involving characterization of active site derived peptides and the synthesis and comparative study of model compounds. Sequence homology among four cloned and sequenced eukaryotic CAO's indicates a conserved structural motif toward the C-terminus of protein; this structural motif contains both the TPQ consensus sequence and the putative histidine ligands to copper. The gene for yeast amine oxidase from Hansenula polymorpha (YAO) will be modified for expression of the C-terminal domain, with the goal of determining whether cofactor biogenesis can occur within this domain. Efforts currently underway, to obtain an X-ray structure for YAO will be continued and eventually extended to mutant forms of YAO. Solution studies, focused on both an amine oxidase from bovine plasma and YAO, will address a number of questions which include the role of the active site consensus sequence in determining substrate specificity, the nature of the active site base catalyzing substrate oxidation, and the chemical mechanism of the half reaction involving reduction of dioxygen to hydrogen peroxide. Given their wide ranging physiologic functions which include the oxidative removal of biogenic amines from the blood stream and the cross-linking of collagen and elastin, the quinoproteins under study are directly related to human health.