SEQUENCE, EXPRESSION, AND FUNCTION OF THE GENE FOR THE NONPHOSPHORYLATING, NADP-DEPENDENT GLYCERALDEHYDE-3-PHOSPHATE DEHYDROGENASE OF STREPTOCOCCUS-MUTANS
SEQUENCE, EXPRESSION, AND FUNCTION OF THE GENE FOR THE NONPHOSPHORYLATING, NADP-DEPENDENT GLYCERALDEHYDE-3-PHOSPHATE DEHYDROGENASE OF STREPTOCOCCUS-MUTANS
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DOI：
10.1128/jb.177.10.2622-2627.1995
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发表时间：
1995-05-01
影响因子：
3.2
通讯作者：
HAMILTON, IR
中科院分区：
文献类型：
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作者：
BOYD, DA;CVITKOVITCH, DG;HAMILTON, IR
我们报告了变形链球菌 NG5 基因组 2,019 bp 区域的测序，该区域包含 1,428 bp 开放阅读框 (ORF)，其假定的翻译产物与来自玉米和豌豆的非磷酸化、NADP 依赖性甘油醛-3-磷酸脱氢酶 (GAPN) 的氨基酸序列具有 50% 的同一性。该 ORF 位于编码磷酸烯醇丙酮酸：糖磷酸转移酶转运系统酶 I 的 ptsI 基因下游约 200 bp。突变体BCH150中推定的gapN基因已失活，缺乏野生型菌株中存在的GAPN活性，因此可以肯定地将ORF鉴定为变形链球菌gapN基因。另一种变形链球菌菌株 DC10（含有插入失活的 ptsI 基因）仍然具有 GAPN 活性，唾液链球菌 ATCC 25975 也是如此，其含有 ptsI 和 gapN 基因之间的插入元件。由于野生型变形链球菌NG5缺乏葡萄糖-6-磷酸脱氢酶和NADH:NADP氧化还原酶活性，因此NADP依赖性甘油醛-3-磷酸脱氢酶作为产生用于生物合成反应的NADPH的手段是重要的。
We report the sequencing of a 2,019-bp region of the Streptococcus mutans NG5 genome which contains a 1,428-bp open reading frame (ORF) whose putative translation product had 50% identity to the amino acid sequences of the nonphosphorylating, NADP-dependent glyceraldehyde-3-phosphate dehydrogenases (GAPN) from maize and pea. This ORF is located approximately 200 bp downstream of the ptsI gene coding for enzyme I of the phosphoenolpyruvate:sugar phosphotransferase transport system. Mutant BCH150, in which the putative gapN gene had been inactivated, lacked GAPN activity that was present in the wild-type strain, thus positively identifying the ORF as the S. mutans gapN gene. Another strain of S. mutans, DC10, which contains an insertionally inactivated ptsI gene, still possessed GAPN activity, as did S. salivarius ATCC 25975, which contains an insertion element between the ptsI and gapN genes. Since the wild-type S. mutans NG5 lacks both glucose-6-phosphate dehydrogenase and NADH:NADP oxidoreductase activities, the NADP-dependent glyceraldehyde-3-phosphate dehydrogenase is important as a means of generating NADPH for biosynthetic reactions.