Identification of the Enterococcus faecalis tyrosine decarboxylase operon involved in tyramine production
Identification of the Enterococcus faecalis tyrosine decarboxylase operon involved in tyramine production
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DOI：
10.1128/aem.68.7.3537-3544.2002
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发表时间：
2002-07-01
影响因子：
4.4
通讯作者：
Prévost, H
中科院分区：
文献类型：
--
作者：
Connil, N;Le Breton, Y;Prévost, H
粪肠球菌插入突变体库的筛选允许分离酪胺生产受影响的突变体。该突变株的生长情况与野生型E. Maijala肉汤中的粪肠球菌JH 2 -2菌株，而高效液相色谱分析表明，酪胺的产生（野生型菌株达到1，000 μ g ml（-1））被完全消除。插入位点的遗传分析揭示了一个基因编码的脱羧酶与真核生物酪氨酸脱羧酶的相似性。序列分析显示磷酸吡哆醛结合位点，表明该酶属于使用该辅因子的氨基酸脱羧酶家族。逆转录-PCR分析表明，编码E. faecalis JH 2 -2与编码推定酪氨酸-酪胺反向转运蛋白的下游基因和上游酪氨酰-tRNA合成酶基因共转录。这项研究是第一次在原核生物中描述酪氨酸脱羧酶基因。
Screening of a library of Enterococcus faecalis insertional mutants allowed isolation of a mutant affected in tyramine production. The growth of this mutant was similar to that of the wild-type E. faecalis JH2-2 strain in Maijala broth, whereas high-performance liquid chromatography analyses showed that tyramine production, which reached 1,000 mug ml(-1) for the wild-type strain, was completely abolished. Genetic analysis of the insertion locus revealed a gene encoding a decarboxylase with similarity to eukaryotic tyrosine decarboxylases. Sequence analysis revealed a pyridoxal phosphate binding site, indicating that this enzyme belongs to the family of amino acid decarboxylases using this cofactor. Reverse transcription-PCR analyses demonstrated that the gene (tdc) encoding the putative tyrosine decarboxylase of E. faecalis JH2-2 is cotranscribed with the downstream gene encoding a putative tyro sine-tyramine antiporter and with the upstream tyrosyl-tRNA synthetase gene. This study is the first description of a tyrosine decarboxylase gene in prokaryotes.