GENETIC-CHARACTERIZATION OF POLYPEPTIDE DEFORMYLASE, A DISTINCTIVE ENZYME OF EUBACTERIAL TRANSLATION
GENETIC-CHARACTERIZATION OF POLYPEPTIDE DEFORMYLASE, A DISTINCTIVE ENZYME OF EUBACTERIAL TRANSLATION
复制标题
DOI：
10.1002/j.1460-2075.1994.tb06335.x
复制
发表时间：
1994-02-15
期刊：
影响因子：
11.4
通讯作者：
MARLIERE, P
中科院分区：
文献类型：
--
作者：
MAZEL, D;POCHET, S;MARLIERE, P
脱甲酰基酶通过从核糖体合成的多肽的N-末端蛋氨酸残基中去除甲酰基，在真细菌蛋白质的成熟过程中起着至关重要的作用。尽管这种酶在翻译中起着重要的作用，但由于其不稳定性，到目前为止还没有对其进行表征。我们报道了通过从高拷贝数的质粒中高效表达基因组文库并选择底物类似物甲酰-亮氨酰-蛋氨酸作为蛋氨酸来源来分离大肠杆菌def的变形酶基因。Def基因编码169个氨基酸的多肽，与其他已知蛋白质没有明显的相似之处。它与fmt基因形成操纵子，编码启动子甲硫酰-tRNA(I)转换酶，最近对其进行了表征(Guillon等人，J.细菌，174,4294-4301,1992)。该操纵子被定位在大肠杆菌染色体的第72位。如果fmt基因也失活，或者甲硫氨酰-tRNA(I)转化中的甲酰基供体N10-甲酰基-四氢叶酸的生物合成被甲氧普林阻断，def基因可能被灭活。这些发现表明脱甲酰酶是抗菌化疗的靶点。
Deformylase performs an essential step in the maturation of proteins in eubacteria, by removing the formyl group from the N-terminal methionine residue of ribosome-synthesized polypeptides. In spite of this important role in translation, the enzyme had so far eluded characterization because of its instability. We report the isolation of the deformylase gene of Escherichia coli, def, by overexpression of a genomic library from a high-copy-number plasmid and selection for utilization of the substrate analogue formyl-leucyl-methionine as a source of methionine. The def gene encodes a 169 amino acid polypeptide that bears no obvious resemblance to other known proteins. It forms an operon with the fmt gene, that encodes the initiator methionyl-tRNA(i) transformylase, which was recently characterized (Guillon et al., J. Bacteriol., 174, 4294-4301, 1992). This operon was mapped at min 72 of the E.coli chromosome. The def gene could be inactivated if the fmt gene was also inactivated, or if biosynthesis of N10-formyl-tetrahydrofolate, the formyl donor in methionyl-tRNA(i) transformylation, was blocked by trimethoprim. These findings designate deformylase as a target for antibacterial chemotherapy.