Crystal structure of the yeast nicotinamidase Pnc1p
Crystal structure of the yeast nicotinamidase Pnc1p
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DOI：
10.1016/j.abb.2007.01.037
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发表时间：
2007-05-01
影响因子：
3.9
通讯作者：
Hart, P. John
中科院分区：
文献类型：
--
作者：
Hu, Gang;Taylor, Alexander B.;Hart, P. John
酵母烟酰胺酶Pnc1p通过降低烟酰胺的水平而在转录沉默中起作用，烟酰胺是历史性脱乙酰酶Sir2p的抑制剂。Pnc1p的结构确定在2.9 A分辨率使用MAD和MIRAS定相方法后，无意中结晶在追求的组氨酸标记的酵母异柠檬酸脱氢酶（IDH）的结构。Pnc1p显示一簇表面组氨酸残基可能负责其与IDH从Ni2+偶联色谱树脂共分馏。在酵母中表达组氨酸标记蛋白的研究人员应该意识到Pnc1p结晶的倾向，即使在浓度被感兴趣的蛋白质淹没时。蛋白质组装成延伸的螺旋阵列，交织在一起，形成一个异常坚固，但多孔的超结构。Pnc1p结构与三种同源细菌蛋白质的比较揭示了一个共同的核心折叠，每个蛋白质都有独特的氨基酸插入。这些插入介导的自我相互作用，定义了不同的高阶低聚状态，这些分子达到。Pnc1p还作用于吡嗪酰胺，吡嗪酰胺是一种底物类似物，由结核分枝杆菌的烟酰胺酶转化为对该生物体有毒的产物。然而，我们没有发现药物对酵母细胞生长有害影响的证据。(c)2007年爱思唯尔公司All rights reserved.
The yeast nicotinamidase Pnc1p acts in transcriptional silencing by reducing levels of nicotinamide, an inhibitor of the historic deacetylase Sir2p. The Pnc1p structure was determined at 2.9 A resolution using MAD and MIRAS phasing methods after inadvertent crystallization during the pursuit of the structure of histidine-tagged yeast isocitrate dehydrogenase (IDH). Pnc1p displays a cluster of surface histidine residues likely responsible for its co-fractionation with IDH from Ni2+-coupled chromatography resins. Researchers expressing histidine-tagged proteins in yeast should be aware of the propensity of Pnc1p to crystallize, even when overwhelmed in concentration by the protein of interest. The protein assembles into extended helical arrays interwoven to form an unusually robust, yet porous superstructure. Comparison of the Pnc1p structure with those of three homologous bacterial proteins reveals a common core fold punctuated by amino acid insertions unique to each protein. These insertions mediate the self-interactions that define the distinct higher order oligomeric states attained by these molecules. Pnc1p also acts on pyrazinamide, a substrate analog converted by the nicotinamidase from Mycobacterium tuberculosis into a product toxic to that organism. However, we find no evidence for detrimental effects of the drug on yeast cell growth. (c) 2007 Elsevier Inc. All rights reserved.