Cloning of a Neisseria meningitidis gene for L-lactate dehydrogenase (L-LDH): Evidence for a second meningococcal L-LDH with different regulation
Cloning of a Neisseria meningitidis gene for L-lactate dehydrogenase (L-LDH): Evidence for a second meningococcal L-LDH with different regulation
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DOI：
10.1128/jb.178.16.4807-4813.1996
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发表时间：
1996-08-01
影响因子：
3.2
通讯作者：
Gotschlich, EC
中科院分区：
文献类型：
--
作者：
Erwin, AL;Gotschlich, EC
我们报道了脑膜炎奈瑟菌l -乳酸脱氢酶（L-LDH）基因lldA的克隆，大肠杆菌在l -乳酸脱氢酶的操纵子中含有单个L-LDH基因（lldD），大肠杆菌在复杂培养基中生长不具有L-LDH活性，但在以l -乳酸为碳源的特定培养基中生长可诱导其活性。相反，脑膜炎球菌除了含有lldA基因产物外，还含有至少一种L-LDH。这些酶在复杂培养基中生长的脑膜炎球菌中有活性，不依赖于l -乳酸盐的生长。预测的lldA氨基酸序列与大肠杆菌lldD和其他原核和真核黄素单核苷酸酶同源，这些酶催化l -乳酸和其他小α -羟基酸的氧化。发现lld4缺失的突变体具有降低的L-LDH活性。然而，这个突变体能够在l -乳酸盐上生长，这表明一定存在第二个L-LDH。lldA酶的活性受生长条件的影响，在以l -乳酸或丙酮酸为碳源的特定培养基上生长可以提高lldA酶的活性。对于在复杂培养基上生长的脑膜炎球菌，在平板上或在通气良好的肉汤中生长可以提高lldA酶的活性。第二种l -乳酸氧化活性见于在不通风的肉汤中生长的细菌。淋病奈瑟菌含有lda的同源物。至于脑膜炎球菌，淋球菌的lldA突变降低了L-LDH活性，但对l -乳酸的生长没有影响。
We report the cloning of lldA, a Neisseria meningitidis gene for L-lactate dehydrogenase (L-LDH), Escherichia coli contains a single L-LDH gene (lldD) in the lld operon (previously lct), E. coli grown in complex media does not have L-LDH activity, but the activity is induced by growth in defined medium with L-lactate as the carbon source. In contrast, meningococci contain at least one L-LDH in addition to the lldA gene product. These enzymes are active in meningococci grown in complex media and are not dependent on growth in L-lactate. The predicted amino acid sequence of lldA is homologous to that of E. coli lldD and of other prokaryotic and eukaryotic flavin mononucleotide containing enzymes that catalyze the oxidation of L-lactate and other small alpha-hydroxy acids. A mutant with a deletion in lld4 was found to have reduced L-LDH activity. However, this mutant was able to grow on L-lactate, indicating that a second L-LDH must exist. Activity of the lldA enzyme was affected by growth conditions, being increased by growth on a defined medium with either L-lactate or pyruvate as the carbon source. For meningococci grown on a complex medium, activity of the lldA enzyme was increased by growth on plates or in well-aerated broth. A second L-lactate-oxidizing activity was seen in bacteria grown in poorly aerated broth. Neisseria gonorrhoeae contains a homolog of lldA. As for meningococci, mutation of the gonococcal lldA reduced L-LDH activity but did not affect growth on L-lactate.