Lawrence B A, Suarez C, DePina A, Click E, Kolodny N H, Allen M M
Department of Biological Sciences, Wellesley College, Wellesley, MA 02181, USA.
Arch Microbiol. 1998 Mar;169(3):195-200. doi: 10.1007/s002030050560.
Two intracellular pools of soluble polyphosphate were identified by in vivo 31P NMR spectroscopy in the cyanobacterium Synechocystis sp. strain PCC 6308. Polyphosphate was present in the cells after growth in sulfur-limited media containing excess phosphate. The presence of polyphosphate was confirmed by transmission electron microscopy and chemical analysis. 31P NMR spectroscopy of whole cells treated with EDTA revealed two pools of mobile polyphosphate. A downfield shift and narrowing of part of the broad polyphosphate resonance was observed after EDTA treatment, suggesting that EDTA binds metal ions normally associated with some of the polyphosphate. Phosphate, but not polyphosphate, leaked out of the cells after this treatment. Addition of magnesium ions caused the downfield shift in the polyphosphate resonance to move back toward its original value. These data show that only part of the cation-complexed polyphosphate is accessible to the added EDTA and suggest that there are two internal fractions of NMR-visible polyphosphate in the cells, only one of which loses its associated cations to EDTA. Spheroplast formation showed that polyphosphate was not present in the periplasm of the cells.
通过体内³¹P核磁共振光谱法，在集胞藻PCC 6308菌株中鉴定出了两个可溶性多聚磷酸盐的细胞内池。在含有过量磷酸盐的硫限制培养基中生长后，细胞中存在多聚磷酸盐。通过透射电子显微镜和化学分析证实了多聚磷酸盐的存在。用EDTA处理的全细胞的³¹P核磁共振光谱显示有两个可移动的多聚磷酸盐池。EDTA处理后，观察到宽的多聚磷酸盐共振的一部分发生了向下场移动和变窄，这表明EDTA结合了通常与一些多聚磷酸盐相关的金属离子。处理后，磷酸盐而非多聚磷酸盐从细胞中泄漏出来。添加镁离子导致多聚磷酸盐共振的向下场移动回到其原始值。这些数据表明，添加的EDTA只能接触到部分阳离子络合的多聚磷酸盐，这表明细胞内有两个核磁共振可见的多聚磷酸盐内部组分，其中只有一个会将其相关阳离子释放给EDTA。原生质球的形成表明细胞周质中不存在多聚磷酸盐。
