作者:Kathrin Gilg、Tobias Mayer、Natascha Ghaschghaie、Peter Klüfers
DOI:10.1039/b909431h
日期:——
In aqueous solution, the reducing sugar phosphates D-arabinose 5-phosphate, D-ribose 5-phosphate, D-fructose 1,6-bisphosphate, D-fructose 6-phosphate, D-glucose 6-phosphate and D-mannose 6-phosphate provide metal-binding sites at their glycose core on reaction with PdII(en) or MIII(tacn) residues (M = Ga, Co; en = ethylenediamine, tacn = 1,4,7-triazacyclononane). The individual species were detected by one- and two-dimensional NMR spectroscopy. The coordination patterns are related to the metal-binding modes of the respective parent glycoses. In detail, ribo- and arabinofuranose phosphate favour κO1,3 coordination, whereas the ketofuranose core of fructose phosphate and fructose bisphosphate provides the κO2,3 chelator thus maintaining the configuration of the respective major solution anomer. On palladium excess, D-fructose 6-phosphate is metallated twice in a unique κO1,3 : κO2,4 metallation pattern. Dimetallation is also found for the aldohexose phosphates. A mixed glycose-core–phosphate chelation was detected for PdII(en) and MIII(tacn) residues with M = Al, Ga in the pH range just above the physiological pH for the D-fructose 1,6-bisphosphate ligand. The results are discussed in relation to D-fructose-1,6-bisphosphate-metabolism in class-II aldolases.
在
水溶液中,还原糖
磷酸盐 D-arabinose 5-
磷酸、D-ribose 5-
磷酸、D-fructose 1,6-bisphosphate、D-fructose 6-
磷酸、D-glucose 6-
磷酸和 D-mannose 6-
磷酸在与 PdII(en) 或 MIII(tacn) 残基(M = Ga、Co;en=
乙二胺,tacn=
1,4,7-三氮杂环壬烷)反应时,在其糖核上提供
金属结合位点。通过一维和二维核磁共振光谱检测了各个物种。配位模式与各自母糖苷的
金属结合模式有关。具体来说,
核糖和阿拉伯
呋喃糖
磷酸有利于κO1,3 配位,而
果糖磷酸和
果糖双
磷酸的酮
呋喃糖核心提供了κO2,3
螯合剂,从而保持了各自主要溶液异构体的构型。在
钯过量时,
D-果糖 6-
磷酸会以独特的 κO1,3 : κO2,4
金属化模式发生两次
金属化。在醛己糖
磷酸盐中也发现了二
金属化现象。PdII(en) 和 MIII(tacn) 残基(M = Al、Ga)在略高于 1,6-二
磷酸果糖配体生理 pH 值的 pH 范围内检测到一种混合的糖核
磷酸盐螯合作用。研究结果与第二类
醛缩酶中的
D-果糖-1,6-二
磷酸代谢有关。