Inhibition and structure of Trichomonas vaginalis purine nucleoside phosphorylase with picomolar transition state analogues.
Inhibition and structure of Trichomonas vaginalis purine nucleoside phosphorylase with picomolar transition state analogues.
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皮摩尔过渡态类似物对阴道毛滴虫嘌呤核苷磷酸化酶的抑制和结构。
DOI：
10.1021/bi061515r
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发表时间：
2007
期刊：
影响因子：
2.9
通讯作者：
Schramm,VernL
中科院分区：
文献类型：
--
作者：
Rinaldo-Matthis,Agnes;Wing,Corin;Ghanem,Mahmoud;Deng,Hua;Wu,Peng;Gupta,Arti;Tyler,PeterC;Evans,GaryB;Furneaux,RichardH;Almo,StevenC;Wang,ChingC;Schramm,VernL
阴道毛滴虫是一种嘌呤营养不良的寄生原生动物，具有独特的嘌呤回收途径，由细菌型嘌呤核苷磷酸化酶（PNP）和嘌呤核苷激酶组成。因此,T。阴道ispnp （TvPNP）的作用方向与其他生物体中的pnp相反。Immucillin-A （ImmA）和DADMe-ImmA是腺苷的过渡态模拟物，具有几何和静电特征，类似于TvPNP稳定过渡态下腺苷的早期和晚期过渡态。ImmA对TvPNP表现出缓慢的紧密结合抑制作用，其平衡解离常数为87 pM，抑制剂释放半衰期为17.2 min， aKm/Kdratio为70,100。DADMe-ImmA类似于TvPNP的晚期核糖体碳离子过渡态，其解离常数为30 pM，抑制剂释放半衰期为64 min， aKm/Kdratio为203,300。DADMe-ImmA的紧密结合支持SN1晚期过渡状态。尽管ImmA和DADMe-ImmA与TvPNP紧密结合，但它们是human和p的弱抑制剂。falciparumPNPs。TvPNP·ImmA·po4和TvPNP·DADMe-ImmA·po4三元配合物的晶体结构与以往底物类似物的结构不同。与DADMe-ImmA的紧密结合部分是由于po4氧与羟基吡啶的N1′阳离子之间的2.7 Å离子相互作用，并且在3.5 Å的TvPNP·ImmA·po4结构中较弱。然而，TvPNP·ImmA·PO4结构包括2 ' -羟基与蛋白质之间的氢键，而这些氢键在TvPNP·DADMe-ImmA·PO4中不存在。这些结构解释了为什么DADMe-ImmA比ImmA结合更紧密。Immucillin-H是TvPNP的12 nM抑制剂，但人类PNP的56 pM抑制剂。用[6-18O] imh的同位素编辑差异红外光谱解释了这一差异，确定O6是TvPNP·imh·PO4中的酮互变异构体，造成了不利的离基相互作用。
Trichomonas vaginalisis a parasitic protozoan purine auxotroph possessing a unique purine salvage pathway consisting of a bacterial type purine nucleoside phosphorylase (PNP) and a purine nucleoside kinase. Thus,T. vaginalisPNP (TvPNP) functions in the reverse direction relative to the PNPs in other organisms. Immucillin-A (ImmA) and DADMe-Immucillin-A (DADMe-ImmA) are transition state mimics of adenosine with geometric and electrostatic features that resemble early and late transition states of adenosine at the transition state stabilized by TvPNP. ImmA demonstrates slow-onset tight-binding inhibition with TvPNP, to give an equilibrium dissociation constant of 87 pM, an inhibitor release half-time of 17.2 min, and aKm/Kdratio of 70,100. DADMe-ImmA resembles a late ribooxacarbenium ion transition state for TvPNP to give a dissociation constant of 30 pM, an inhibitor release half-time of 64 min, and aKm/Kdratio of 203,300. The tight binding of DADMe-ImmA supports a late SN1 transition state. Despite their tight binding to TvPNP, ImmA and DADMe-ImmA are weak inhibitors of human andP. falciparumPNPs. The crystal structures of the TvPNP·ImmA·PO4and TvPNP·DADMe-ImmA·PO4ternary complexes differ from previous structures with substrate analogues. The tight binding with DADMe-ImmA is in part due to a 2.7 Å ionic interaction between a PO4oxygen and the N1‘ cation of the hydroxypyrrolidine and is weaker in the TvPNP·ImmA·PO4structure at 3.5 Å. However, the TvPNP·ImmA·PO4structure includes hydrogen bonds between the 2‘-hydroxyl and the protein that are not present in TvPNP·DADMe-ImmA·PO4. These structures explain why DADMe-ImmA binds tighter than ImmA. Immucillin-H is a 12 nM inhibitor of TvPNP but a 56 pM inhibitor of human PNP. And this difference is explained by isotope-edited difference infrared spectroscopy with [6-18O]ImmH to establish that O6 is the keto tautomer in TvPNP·ImmH·PO4, causing an unfavorable leaving-group interaction.
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影响因子：
2.1
作者：
Annette M. Gero;Edward W. Kang;Jo E. Harvey;Philip J. Schofield;Keith Clinch;R. Furneaux
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DOI：
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影响因子：
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作者：
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通讯作者：
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影响因子：
13.3
作者：
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通讯作者：
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影响因子：
15
作者：
TaylorRingia,ErikaA;Tyler,PeterC;Evans,GaryB;Furneaux,RichardH;Murkin,AndrewS;Schramm,VernL
通讯作者：
Schramm,VernL