Xenon and halogenated alkanes track putative substrate binding cavities in the soluble methane monooxygenase hydroxylase.
Xenon and halogenated alkanes track putative substrate binding cavities in the soluble methane monooxygenase hydroxylase.
复制标题
氙和卤代烷烃追踪可溶性甲烷单加氧酶羟化酶中假定的底物结合腔。
DOI：
10.1021/bi0022487
复制
发表时间：
2001
期刊：
影响因子：
2.9
通讯作者：
Lippard,SJ
中科院分区：
文献类型：
--
作者：
Whittington,DA;Rosenzweig,AC;Frederick,CA;Lippard,SJ
为了研究可溶性甲烷单加氧酶羟化酶（MMOH）中蛋白质空腔在促进底物甲烷和分子氧运动中的作用，我们测定了与二溴甲烷或碘乙烷共结晶的荚膜甲基球菌（Bath）MMOH的X射线结构，以及用氙气加压的晶体。卤代烷结合在α亚基内的两个空腔中，从蛋白质的一个表面延伸到埋藏的双核铁活性位点。另外两个结合位点位于β亚基中。用氙对MMOH的两种晶型加压，鉴定出仅位于α亚基中的6个结合位点。这些结果表明，疏水性物质优先结合在MMOH中预先存在的空腔，并支持这样的空腔可能在螯合和增强活性位点反应的生理底物的可用性方面发挥功能作用的假设。
To investigate the role of protein cavities in facilitating movement of the substrates, methane and dioxygen, in the soluble methane monooxygenase hydroxylase (MMOH), we determined the X-ray structures of MMOH fromMethylococcus capsulatus(Bath) cocrystallized with dibromomethane or iodoethane, or by using crystals pressurized with xenon gas. The halogenated alkanes bind in two cavities within the α-subunit that extend from one surface of the protein to the buried dinuclear iron active site. Two additional binding sites were located in the β-subunit. Pressurization of two crystal forms of MMOH with xenon resulted in the identification of six binding sites located exclusively in the α-subunit. These results indicate that hydrophobic species bind preferentially in preexisting cavities in MMOH and support the hypothesis that such cavities may play a functional role in sequestering and enhancing the availability of the physiological substrates for reaction at the active site.