TRK2不是酿酒酵母中的低亲和力钾转运体。
TRK2 is not a low-affinity potassium transporter in Saccharomyces cerevisiae.
作者信息
Ramos J, Alijo R, Haro R, Rodriguez-Navarro A
机构信息
Departamento de Microbiología, Escuela Técnica Superior de Ingenieros Agrónomos, Córdoba, Spain.
出版信息
J Bacteriol. 1994 Jan;176(1):249-52. doi: 10.1128/jb.176.1.249-252.1994.
TRK1 and TRK2 encode proteins involved in K+ uptake in Saccharomyces cerevisiae. A kinetic study of Rb+ influx in trk1 TRK2, trk1 TRK2D, and trk1 trk2 mutants reveals that TRK2 shows moderate affinity for Rb+. K(+)-starved trk1 delta TRK2 cells show a low-affinity component accounting for almost the total Vmax of the influx and a moderate-affinity component exhibiting a very low Vmax. Overexpression of TRK2 in trk1 delta TRK2D cells increases the Vmax of the moderate-affinity component, and this component disappears in trk1 delta trk2 delta cells. In contrast, the low-affinity component of Rb+ influx in trk1 delta TRK2 cells is not affected by mutations in TRK2. Consistent with the different levels of activity of the moderate-affinity Rb+ influx, trk1 delta TRK2 cells grow slowly in micromolar K+, trk1 delta TRK2D cells grow rapidly, and trk1 delta trk2 delta cells fail to grow. The existence of a unique K+ uptake system composed of several proteins is also discussed.
TRK1和TRK2编码参与酿酒酵母钾离子摄取的蛋白质。对trk1 TRK2、trk1 TRK2D和trk1 trk2突变体中铷离子流入的动力学研究表明，TRK2对铷离子具有中等亲和力。钾离子饥饿的trk1δTRK2细胞显示出一个低亲和力组分，几乎占流入总量的Vmax，以及一个中等亲和力组分，其Vmax非常低。在trk1δTRK2D细胞中过表达TRK2会增加中等亲和力组分的Vmax，并且该组分在trk1δtrk2δ细胞中消失。相反，trk1δTRK2细胞中铷离子流入的低亲和力组分不受TRK2突变的影响。与中等亲和力铷离子流入的不同活性水平一致，trk1δTRK2细胞在微摩尔浓度的钾离子中生长缓慢，trk1δTRK2D细胞生长迅速，而trk1δtrk2δ细胞无法生长。还讨论了由几种蛋白质组成的独特钾离子摄取系统的存在。
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