Lieberman M M, Markovitz A
J Bacteriol. 1970 Mar;101(3):965-72. doi: 10.1128/jb.101.3.965-972.1970.
Mutations in a regulator gene (capR) that causes increased synthesis of capsular polysaccharide and derepressed synthesis of several enzymes involved in polysaccharide synthesis also derepress synthesis of guanosine diphosphate (GDP)-mannose pyrophosphorylase. In addition, a second mucoid mutation (capS, which maps separately from capR) also results in the derepression of GDP-mannose pyrophosphorylase. New conditions for assaying GDP-mannose hydrolyase and GDP-l-fucose synthetase permitted us to show that these enzymes are also derepressed in the capS mucoid strain. Although phosphomannose isomerase and uridine diphosphate-galactose-4-epimerase are derepressed in capR mucoid strains, they are not derepressed in capS mucoid strains. A nonmucoid mutant of a strain containing the capR9 (mucoid) allele was deficient in GDP-mannose pyrophosphorylase.
调节基因（capR）发生突变会导致荚膜多糖合成增加，同时参与多糖合成的几种酶的合成去阻遏，这也会使二磷酸鸟苷（GDP）-甘露糖焦磷酸化酶的合成去阻遏。此外，第二个黏液样突变（capS，其定位与capR不同）也会导致GDP-甘露糖焦磷酸化酶的去阻遏。用于检测GDP-甘露糖水解酶和GDP-L-岩藻糖合成酶的新条件使我们能够证明，这些酶在capS黏液样菌株中也被去阻遏。虽然磷酸甘露糖异构酶和尿苷二磷酸-半乳糖-4-表异构酶在capR黏液样菌株中被去阻遏，但在capS黏液样菌株中并未被去阻遏。含有capR9（黏液样）等位基因的菌株的非黏液样突变体缺乏GDP-甘露糖焦磷酸化酶。
