Combeau C, Carlier M F
Laboratoire d'Enzymologie du Centre National de la Recherche Scientifique, Gif-sur-Yvette, France.
J Biol Chem. 1989 Nov 15;264(32):19017-21.
Aluminum fluoride and beryllium fluoride complexes have previously been shown to bind tightly to F-ADP-actin and GDP-microtubules in competition with Pi and to mimic the XDP-Pi transient state of the polymerization. The structure of the bound complexes is investigated here in further detail. Using a fluoride ion-specific electrode, the number of fluoride atoms per aluminum or beryllium atom in the bound complex could be determined. The results indicate that AIF-4 and either BeF2(OH)-.H2O or BeF3-.H2O are the tightly bound species in both F-actin and microtubules. The dependences of the binding on pF and pH are consistent with this conclusion. The possible geometries of aluminum and beryllium fluorides in the gamma-phosphate subsite of the nucleotide are discussed in correlation with the catalytic mechanism of nucleotide hydrolysis.
先前已表明，氟化铝和氟化铍络合物能与磷酸根竞争，紧密结合到F-ADP-肌动蛋白和GDP-微管上，并模拟聚合反应的XDP-磷酸根瞬态。本文进一步详细研究了结合络合物的结构。使用氟离子特异性电极，可以确定结合络合物中每个铝或铍原子的氟原子数。结果表明，AIF-4以及BeF2(OH)-H₂O或BeF3-H₂O是F-肌动蛋白和微管中紧密结合的物种。结合对pF和pH的依赖性与该结论一致。结合核苷酸γ-磷酸亚位点中铝和铍氟化物的可能几何结构，讨论了核苷酸水解的催化机制。
