EXAFS STUDY OF NOVEL NONHEME DIIRON HYDROXYLASES

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。 未活化的C-H键的羟基化是一种具有重要基础和实用价值的转化。细菌多组分加氧酶(BMMS)家族是一类广为人知的能够进行这种转化的酶，它利用四螺旋束蛋白折叠(Alpha4)为其双铁活性部位提供2组氨酸和4羧酸配体[1]。我们目前正在研究两种新的双铁酶，脱氧亚硫氨酸羟基酶(DOHH)和CmlA，它们影响这种转化。虽然这两种酶的晶体结构尚未获得，但序列分析表明，DOHH[2]和CmlA[3]都明显偏离了BMMS高度保守的结构基序。此外，与BMMS不同的是，DOHH和CmlA只与蛋白质结合的底物反应，它们的羟基化是严格立体专一性的。

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. The hydroxylation of unactivated C-H bond is a transformation of great fundamental and practical interest. A well known class of enzymes capable of this transformation is the bacterial multicomponent mooxygenases (BMMs)family utilizing four-helix bundle protein folds (alpha4) to provide 2 His and 4 carboxylate ligands to their diiron active sites [1]. We are currently investigating two novel diiron enzymes, deoxyhypusine hydroxylase (DOHH) and CmlA, that effect this transformation. Although crystal structures of these two enzymes have not been obtained, sequence analysis indicates that both DOHH [2] and CmlA [3] remarkably deviate from the highly conserved structural motif of BMMs. In addition, unlike BMMs, DOHH and CmlA only react with protein-bound substrates and their hydroxylation is strictly stereospecific.