School of Biological Sciences, University of Nebraska, Lincoln, NE 68588-0666, USA.
FEMS Yeast Res. 2010 Mar;10(2):209-13. doi: 10.1111/j.1567-1364.2010.00602.x. Epub 2010 Jan 21.
The higher fungi exhibit a dichotomy with regard to urea utilization. The hemiascomycetes use urea amidolyase (DUR1,2), whereas all other higher fungi use the nickel-containing urease. Urea amidolyase is an energy-dependent biotin-containing enzyme. It likely arose before the Euascomycete/Hemiascomycete divergence c. 350 million years ago by insertion of an unknown gene into one copy of a duplicated methylcrotonyl CoA carboxylase (MccA). The dichotomy between urease and urea amidolyase coincides precisely with that for the Ni/Co transporter (Nic1p), which is present in the higher fungi that use urease and is absent in those that do not. We suggest that the selective advantage for urea amidolyase is that it allowed the hemiascomycetes to jettison all Ni(2+)- and Co(2+)-dependent metabolisms and thus to have two fewer transition metals whose concentrations need to be regulated. Also, the absence of MccA in the hemiascomycetes coincides with and may explain their production of fusel alcohols.
高等真菌在利用尿素方面表现出二分性。半子囊菌使用尿素酰胺酶（DUR1,2），而所有其他高等真菌则使用含镍的脲酶。尿素酰胺酶是一种依赖能量的含生物素的酶。它可能在 3.5 亿年前的 Euascomycete/Hemiascomycete 分化之前就出现了，通过将一个未知基因插入到一个重复的甲基戊烯酰辅酶 A 羧化酶（MccA）的一个拷贝中。脲酶和尿素酰胺酶之间的二分性与镍/钴转运蛋白（Nic1p）完全吻合，后者存在于使用脲酶的高等真菌中，而不存在于不使用脲酶的高等真菌中。我们认为，尿素酰胺酶的选择优势在于，它允许半子囊菌放弃所有依赖 Ni(2+)和 Co(2+)的代谢途径，从而减少了两种需要调节浓度的过渡金属。此外，半子囊菌中缺乏 MccA 也与它们产生杂醇酒精的情况相符，并可能对此做出解释。
