Plasmodium falciparum Sir2 is an NAD+-dependent deacetylase and an acetyllysine-dependent and acetyllysine-independent NAD+ glycohydrolase.
Plasmodium falciparum Sir2 is an NAD+-dependent deacetylase and an acetyllysine-dependent and acetyllysine-independent NAD+ glycohydrolase.
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DOI：
10.1021/bi800767t
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发表时间：
2008-09-23
期刊：
影响因子：
2.9
通讯作者：
Sauve, Anthony A.
中科院分区：
文献类型：
--
作者：
French, Jarrod B.;Cen, Yana;Sauve, Anthony A.
Sirtuins是依赖于NAD+的酶，它使多种细胞蛋白去乙酰化，在某些情况下催化蛋白质adp -核糖基转移。去乙酰化的催化机制被认为涉及adpr -肽酰化，而adp -核糖基转移到蛋白质的机制尚未确定。在这里，我们描述了恶性疟原虫sirtuin催化组蛋白肽序列的去乙酰化。有趣的是，这种酶还能水解NAD+。鉴定并表征了两种水解机理。一种不依赖于乙酰赖氨酸底物，与甲醇反应生成α-1- o -甲基- adpr，产生α-立体化学。该反应对烟酰胺抑制不敏感。第二种溶剂溶解机制依赖于乙酰化肽，并被提出涉及咪酯生成β-立体化学。以甲醇为助溶剂，通过分离得到β-1- o-甲基- adpr，建立了立体化学反应。这一溶解反应被烟酰胺抑制，表明烟酰胺和溶剂竞争吡酯。这些发现建立了野生型sirtuins的新反应，并提出了adp核糖基化到蛋白质的可能机制。这些发现也说明了烟酰胺作为sirtuin催化adp -核糖基转移机制的探针的潜在效用。
Sirtuins are NAD+-dependent enzymes that deacetylate a variety of cellular proteins and in some cases catalyze protein ADP-ribosyltransfer. The catalytic mechanism of deacetylation is proposed to involve an ADPR-peptidylimidate, whereas the mechanism of ADP-ribosyltransfer to proteins is undetermined. Herein we characterize a Plasmodium falciparum sirtuin that catalyzes deacetylation of histone peptide sequences. Interestingly, the enzyme can also hydrolyze NAD+. Two mechanisms of hydrolysis were identified and characterized. One is independent of acetyllysine substrate and produces α-stereochemistry as established by reaction of methanol which forms α-1-O-methyl-ADPR. This reaction is insensitive to nicotinamide inhibition. The second solvolytic mechanism is dependent on acetylated peptide and is proposed to involve the imidate to generate β-stereochemistry. Stereochemistry was established by isolation of β-1-O-methyl-ADPR when methanol was added as a co-solvent. This solvolytic reaction was inhibited by nicotinamide, suggesting that nicotinamide and solvent compete for the imidate. These findings establish new reactions of wildtype sirtuins and suggest possible mechanisms for ADP-ribosylation to proteins. These findings also illustrate the potential utility of nicotinamide as a probe for mechanisms of sirtuin catalyzed ADP-ribosyltransfer.
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影响因子：
64.8
作者：
Guarente, Leonard
通讯作者：
Guarente, Leonard
影响因子：
--
作者：
Merrick, Catherine J.;Duraisingh, Manoj T.
通讯作者：
Duraisingh, Manoj T.
影响因子：
4.8
作者：
Liszt, G;Ford, E;Guarente, L
通讯作者：
Guarente, L
影响因子：
11.4
作者：
García-Salcedo, JA;Gijón, P;Pays, E
通讯作者：
Pays, E
影响因子：
16
作者：
Avalos, JL;Bever, KM;Wolberger, C
通讯作者：
Wolberger, C