Guest J R
J Gen Microbiol. 1979 Dec;115(2):259-71. doi: 10.1099/00221287-115-2-259.
Fifteen independent menaquinone biosynthesis mutants (men) of Escherichia coli K12, selected for their inability to use fumarate as terminal electron acceptor, were investigated. Two nutritionally distinct groups were detected. The major group (13 mutants) responded to 1,4-dihydroxy-2-naphthoate (DHN), 2-succinylbenzoate (SB) and its dilactone, whereas the minor group (2 mutants) only responded to DHN. DHN was at least five times more effective than SB but it inhibited growth at concentrations greater than 10 microM. For anaerobic growth on glucose minimal medium the auxotrophs responded to much lower concentrations of DHN and SB and these intermediates could be replaced by uracil. Anaerobic growth tests showed that glycerol, formate and H2 are good substrates for E. coli when fumarate is the ultimate electron acceptor but growth with lactate or with fumarate alone is poor. All 15 men mutations were located between glpT and purF at approximately 49 min in the E. coli linkage map. Cotransduction frequencies with relevant markers were: nalA (21%), glpT (35%) and purF (15%). The presence of at least three genetically distinct classes (menC and menD, SB-requirers; menB, DHN-requirers) was indicated using abortive transduction as a complementation test and three-factor genetic analysis. The relative orientation nalA...menC-(D,B)...purF was indicated. Fluoroacetate-resistant mutants were isolated and four different classes were identified: ack, lacking acetate kinase; pta, lacking phosphotransacetylase; facA, lacking both of these activities; and facB, which retained both of these enzyme activities. Some of the pta mutants and all of the facA mutants failed to grow on media containing fumarate as terminal electron acceptor or anaerobically on glucose minimal medium. All four types had genetic lesions clustered between the men and purF sites. Average cotransduction frequencies with relevant markers were: nalA (4%), men (27 to 35%) and purF (71 to 80%).
对15个独立的大肠杆菌K12甲萘醌生物合成突变体（men）进行了研究，这些突变体因无法利用富马酸作为末端电子受体而被筛选出来。检测到两个营养特性不同的组。主要组（13个突变体）对1,4 - 二羟基 - 2 - 萘甲酸（DHN）、2 - 琥珀酰苯甲酸（SB）及其双内酯有反应，而次要组（2个突变体）仅对DHN有反应。DHN的效果至少比SB高五倍，但在浓度大于10微摩尔时会抑制生长。对于在葡萄糖基本培养基上的厌氧生长，营养缺陷型对低得多浓度的DHN和SB有反应，并且这些中间体可以被尿嘧啶替代。厌氧生长试验表明，当富马酸是最终电子受体时，甘油、甲酸和氢气是大肠杆菌的良好底物，但单独以乳酸或富马酸生长较差。所有15个men突变位于大肠杆菌连锁图谱中约49分钟处的glpT和purF之间。与相关标记的共转导频率为：nalA（21%）、glpT（35%）和purF（15%）。使用流产转导作为互补试验和三因子遗传分析表明存在至少三个遗传上不同的类别（menC和menD，需要SB；menB，需要DHN）。表明了nalA...menC - (D,B)...purF的相对方向。分离出了抗氟乙酸突变体，并鉴定出四种不同的类别：ack，缺乏乙酸激酶；pta，缺乏磷酸转乙酰酶；facA，同时缺乏这两种活性；以及facB，保留了这两种酶活性。一些pta突变体和所有facA突变体在含有富马酸作为末端电子受体的培养基上或在葡萄糖基本培养基上厌氧生长时不能生长。所有四种类型的遗传损伤都聚集在men和purF位点之间。与相关标记的平均共转导频率为：nalA（4%）、men（27%至35%）和purF（71%至80%）。
