Zoroddu M A, Fruianu M, Dallocchio R, Masia A
Dipartimento di Chimica, Università di Sassari, Italy.
Biometals. 1996 Jan;9(1):91-7. doi: 10.1007/BF00188096.
Vanadium uptake by whole cells and isolated cell walls of the yeast Saccharomyces cerevisiae was studied. When orthovanadate was added to wild-type S. cerevisiae cells growing in rich medium, growth was inhibited as a function of the VO4(3-) concentration and the growth was completely arrested at a concentration of 20 mM of VO4(3-) in YEPD. Electron paramagnetic resonance (EPR) spectroscopy was used to obtain structural and dynamic information about the cell-associated paramagnetic vanadyl ion. The presence of EPR signals indicated that vanadate was reduced by whole cells to the vanadyl ion. On the contrary, no EPR signals were detected after interaction of vanadate with isolated cell walls. A 'mobile' and an 'immobile' species associated in cells with small chelates and with macromolecular sites, respectively, were identified. The value of rational correlation time tau r indicated the relative motional freedom at the macromolecular site. A strongly 'immobilized' vanadyl species bound to polar sites mainly through coulombic attractions was detected after interaction of VO2+ ions with isolated cell walls.
对酿酒酵母全细胞和分离细胞壁对钒的摄取进行了研究。当向在丰富培养基中生长的野生型酿酒酵母细胞中添加原钒酸盐时，生长受到抑制，抑制程度是VO4(3-)浓度的函数，并且在YEPD中VO4(3-)浓度为20 mM时生长完全停止。利用电子顺磁共振（EPR）光谱来获取有关细胞相关顺磁性钒离子的结构和动力学信息。EPR信号的存在表明全细胞将钒酸盐还原为钒离子。相反，钒酸盐与分离细胞壁相互作用后未检测到EPR信号。在细胞中分别鉴定出与小分子螯合物和大分子位点相关的“可移动”和“不可移动”物种。合理相关时间τr的值表明大分子位点处的相对运动自由度。VO2+离子与分离细胞壁相互作用后，检测到一种主要通过库仑吸引力与极性位点结合的强“固定化”钒离子物种。
