ABSTRACTThe utilization pathway for the uptake of NAD and nicotinamide riboside was previously characterized forHaemophilus influenzae. We now report on the cellular location, topology, and substrate specificity of PnuC.pnuCofH. influenzaeis only distantly related topnuCofEscherichia coliandSalmonella entericaserovar Typhimurium. WhenE. coliPnuC was expressed in anH. influenzae pnuCmutant, it was able to take up only nicotinamide riboside and not nicotinamide mononucleotide. Therefore, we postulated that PnuC transporters in general possess specificity for nicotinamide riboside. Earlier studies showed that 3-aminopyridine derivatives (e.g., 3-aminopyridine adenine dinucleotide) are inhibitory forH. influenzaegrowth. By testing characterized strains with mutations in the NAD utilization pathway, we show that 3-aminopyridine riboside is inhibitory toH. influenzaeand is taken up by the NAD-processing and nicotinamide riboside route. 3-Aminopyridine riboside is utilized effectively in apnuC+background. In addition, we demonstrate that 3-aminopyridine adenine dinucleotide resynthesis is produced by NadR. 3-Aminopyridine riboside-resistantH. influenzaeisolates were characterized, and mutations innadRcould be detected. We also tested other species of the familyPasteurellaceae,Pasteurella multocidaandActinobacillus actinomycetemcomitans, and found that 3-aminopyridine riboside does not act as a growth inhibitor; hence, 3-aminopyridine riboside represents an anti-infective agent with a very narrow host range.
ABSTRACTThe utilization pathway for the uptake of NAD and nicotinamide riboside was previously characterized for Haemophilus influenzae.流感嗜血杆菌的 PnuC 与大肠杆菌和伤寒沙门氏菌的 PnuC 只有较远的亲缘关系。当在流感杆菌 pnuC 突变体中表达大肠杆菌 PnuC 时,它只能吸收烟酰胺核糖,而不能吸收烟酰胺单核苷酸。因此,我们推测 PnuC 转运体一般对烟酰胺核苷具有特异性。早先的研究表明,3-氨基吡啶衍生物(如 3-氨基吡啶腺嘌呤二核苷酸)对流感病毒的生长有抑制作用。通过测试在 NAD 利用途径上发生突变的特征菌株,我们发现 3-氨基吡啶核糖苷对流感病毒具有抑制作用,并通过 NAD 处理和烟酰胺核糖苷途径被吸收。3- 氨基吡啶核苷可在 apnuC+ 背景中有效利用。此外,我们还证明 3-氨基吡啶腺嘌呤二核苷酸的再合成是由 NadR 产生的。我们对抗 3-氨基吡啶核苷的流感病毒分离株进行了鉴定,并检测到了 NadR 的突变。我们还检测了巴斯德菌科的其他菌种、多杀性巴斯德菌和放线杆菌,发现 3-氨基吡啶核苷不具有生长抑制作用;因此,3-氨基吡啶核苷是一种宿主范围很窄的抗感染剂。