Interactions between a minimal protein serine/threonine phosphatase and its phosphopeptide substrate sequence
Interactions between a minimal protein serine/threonine phosphatase and its phosphopeptide substrate sequence
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DOI：
10.1074/jbc.271.40.24401
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发表时间：
1996-10-04
影响因子：
4.8
通讯作者：
Barik, S
中科院分区：
文献类型：
--
作者：
Ansai, T;Dupuy, LC;Barik, S
由大肠杆菌噬菌体λ（PP λ）编码的蛋白磷酸酶被发现是丝氨酸/苏氨酸蛋白磷酸酶（PP）的最小催化核心的生物化学和突变标准的等价物。细菌表达的PP 1和PP 5磷酸酶的截短版本，代表与PP λ同源的催化核心，表现出有效的磷酸酶活性。与全长PP 1不同，但与PP λ一样，重组核心可以使用酪蛋白、磷酸对硝基苯酯和多种肽作为底物，并且对冈田酸、微囊藻毒素-LR和胰蛋白酶具有抗性。His（173）、Asp（208）或Arg（221）的突变对PP 1核心蛋白的活性几乎没有影响，表明其与PP λ的同一性比与全长PP 1的同一性更接近。末端缺失的几个氨基酸的核心破坏了他们的活动，支持他们的最小的性质，PP λ突变体的分析表明金属离子结合的基板的影响。PP λ的磷酸肽底物的最小长度似乎是两侧由1或2个氨基酸残基的磷酸化丝氨酸/苏氨酸，N-末端的更有效。
The protein phosphatase encoded by coliphage lambda (PP lambda) was found to be the equivalent of the minimal catalytic core of serine/threonine protein phosphatases (PP) by biochemical and mutational criteria. Bacterially expressed truncated versions of PP1 and PP5 phosphatases, representing the catalytic cores homologous to PP lambda, exhibited potent phosphatase activity. Unlike full-length PP1, but like PP lambda, the recombinant cores could use casein, p-nitrophenyl phosphate, and a wide variety of peptides as substrates and were resistant to okadaic acid, microcystin-LR, and trypsin. Mutations of His(173), Asp(208), or Arg(221) had little effect on the activity of the PP1 core protein, indicating its closer identity with PP lambda than with full-length PP1. Terminal deletions of a few amino acids of the cores destroyed their activity, supporting their minimal nature, Analysis of PP lambda mutants suggested an influence of the substrate on metal ion binding. The minimal length of a phosphopeptide substrate of PP lambda appeared to be a phosphorylated serine/threonine flanked by 1 or 2 amino acid residues on either side, the N-terminal ones being more effective.