Department of Microbiology, University of Illinois, Urbana, Illinois, 61801, USA.
Department of Biochemistry, University of Illinois, Urbana, Illinois, 61801, USA.
Environ Microbiol. 2021 May;23(5):2683-2691. doi: 10.1111/1462-2920.15512. Epub 2021 Apr 18.
Both Enterococcus faecalis and Escherichia coli can undergo abrupt temperature transitions in nature. E. coli changes the composition of its phospholipid acyl chains in response to shifts growth temperature. This is mediated by a naturally temperature sensitive enzyme, FabF (3-ketoacyl-acyl carrier protein synthase II), that elongates the 16 carbon unsaturated acyl chain palmitoleate to the 18 carbon unsaturated acyl chain, cis-vaccenate. FabF is more active at low temperatures resulting in increased incorporation of cis-vaccenoyl acyl chains into the membrane phospholipids. This response to temperature is an intrinsic property of FabF and does not require increased synthesis of the enzyme. We report that the FabF of the very divergent bacterium, E. faecalis, has properties very similar to E. coli FabF and is responsible for changing E. faecalis membrane phospholipid acyl chain composition in response to temperature. Moreover, expression E. faecalis FabF in an E. coli ∆fabF strain restores temperature regulation to the E. coli strain.
粪肠球菌和大肠杆菌都能在自然界中经历急剧的温度转变。大肠杆菌会根据生长温度的变化来改变其磷脂酰基链的组成。这是由一种天然温度敏感的酶 FabF（3-酮酰-酰基辅酶 A 合成酶 II）介导的，该酶将 16 个碳的不饱和酰基棕榈油酸延长为 18 个碳的不饱和酰基顺式-植烷酸。FabF 在低温下更活跃，导致更多的顺式植烷酰基链掺入膜磷脂中。这种对温度的反应是 FabF 的固有特性，不需要增加酶的合成。我们报告称，非常不同的细菌粪肠球菌的 FabF 具有与大肠杆菌 FabF 非常相似的特性，并且负责响应温度改变粪肠球菌膜磷脂酰基链组成。此外，在大肠杆菌 ∆fabF 菌株中表达粪肠球菌 FabF 可恢复大肠杆菌菌株的温度调节。
