A polyphosphate kinase (PPK2) widely conserved in bacteria
A polyphosphate kinase (PPK2) widely conserved in bacteria
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DOI：
10.1073/pnas.262655199
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发表时间：
2002-12-24
影响因子：
11.1
通讯作者：
Kornberg, A
中科院分区：
文献类型：
--
作者：
Zhang, HY;Ishige, K;Kornberg, A
从大肠杆菌中分离到的聚P激酶（PPK，现称为PPK1）可催化ATP末端磷酸合成无机聚磷酸（poly P）。PPK1在许多细菌中高度保守，包括一些主要的病原体，如铜绿假单胞菌。在缺乏ppk1的铜绿假单胞菌的零突变体中，我们发现了一种以前未被表征的PPK活性（称为PPK2），它与ppk1有以下区别：从GTP或ATP合成聚P，对Mn2+的偏好超过Mg2+，以及聚P的刺激。反向反应，聚P驱动核苷二磷酸激酶从GDP合成GTP，比正向反应，从GTP合成聚P高75倍。编码PPK2的基因（PPK2）从纯化近1000倍的蛋白质氨基酸序列中鉴定出来，具有均匀性。5'端位于“保守假设蛋白”的注释基因组序列上游177bp；ppk2 （1,074 bp）编码一个357 aa的蛋白，分子量为40.8 kDa。与PPK2同源的序列存在于铜绿假单胞菌、两种古生菌和32种其他细菌中的另外两种蛋白质中（几乎都含有PPK1）；这些包括根瘤菌、蓝藻菌、链霉菌和一些致病物种。聚p驱动核苷二磷酸激酶活性的独特特征和PPK2的结构方面是随附报告的主题之一。
Synthesis of inorganic polyphosphate (poly P) from the terminal phosphate of ATP is catalyzed reversibly by poly P kinase (PPK, now designated PPK1) initially isolated from Escherichia coli. PPK1 is highly conserved in many bacteria, including some of the major pathogens such as Pseudomonas aeruginosa. In a null mutant of A aeruginosa lacking ppk1, we have discovered a previously uncharacterized PPK activity (designated PPK2) distinguished from PPK1 by the following: synthesis of poly P from GTP or ATP, a preference for Mn2+ over Mg2+, and a stimulation by poly P. The reverse reaction, a poly P-driven nucleoside diphosphate kinase synthesis of GTP from GDP, is 75-fold greater than the forward reaction, poly P synthesis from GTP. The gene encoding PPK2 (ppk2) was identified from the amino acid sequence of the protein purified near 1,000-fold, to homogeneity. The 5'-end is 177 bp upstream of the annotated genome sequence of a "conserved hypothetical protein"; ppk2 (1,074 bp) encodes a protein of 357 aa with a molecular mass of 40.8 kDa. Sequences homologous to PPK2 are present in two other proteins in A aeruginosa, in two Archaea, and in 32 other bacteria (almost all with PPK1 as well); these include rhizobia, cyanobacteria, Streptomyces, and several pathogenic species. Distinctive features of the poly P-driven nucleoside diphosphate kinase activity and structural aspects of PPK2 are among the subjects of an accompanying report.