The ubiquinone precursors, 2-octaprenyl-6-methoxy-1,4-benzoquinone and 2-octaprenyl-3-methyl-6-methoxy-1,4-benzoquinone, were isolated from ubiquinone-deficient mutants of
Escherichia coli
and identified by nuclear magnetic resonance and mass spectrometry. Mutants accumulating 2-octaprenyl-6-methoxy-1,4-benzoquinone and 2-octaprenyl-3-methyl-6-methoxy-1,4-benzoquinone were shown to carry mutations in genes designated
ubiE
and
ubiF
, respectively. The
ubiE
gene was shown to be cotransducible with
metE
(minute 75) and close to two other genes concerned with ubiquinone biosynthesis. The
ubiF
gene was located close to minute 16 by cotransduction with the
lip, gltA
, and
entA
genes.
泛醌的前体物2-辛基-6-甲氧基-1,4-苯醌和2-辛基-3-甲基-6-甲氧基-1,4-苯醌,从泛醌缺乏的大肠杆菌突变体中分离出来,并通过核磁共振和质谱鉴定。积累2-辛基-6-甲氧基-1,4-苯醌和2-辛基-3-甲基-6-甲氧基-1,4-苯醌的突变体分别被证明携带了被指定为ubiE和ubiF的基因突变。ubiE基因被证明与metE(分钟75)共传导,并靠近另外两个与泛醌生物合成有关的基因。ubiF基因通过与lip、gltA和entA基因的共传导,被定位在分钟16附近。