Lippe G, Tanfani F, Di Pancrazio F, Contessi S, Bertoli E, Dabbeni-Sala F
Dipartimento di Scienze e Tecnologie Biomediche, Università di Udine, Italy.
FEBS Lett. 1998 Aug 7;432(3):128-32. doi: 10.1016/s0014-5793(98)00816-3.
FT-IR analysis shows that treatment of F1ATPase with the inhibitors DCCD and Nbf-Cl, in the presence of saturating concentrations of ADP and AMP-PNP and in the absence of Mg2+, does not modify the secondary structure of the enzyme, but significantly modifies its compactness and thermal stability, although to different extents. Nbf-Cl causes a significant increase in stabilisation, in addition to that induced by nucleotides, while DCCD is less effective in this regard. Determination by HPLC of the exchange rate, in the absence of Mg2+, of tightly bound nucleotides of F1ATPase treated with the two inhibitors shows that DCCD does not significantly affect the exchange rate of ADP with AMP-PNP and vice versa in catalytic and non-catalytic tight sites, while Nbf-Cl selectively reduces the enzyme's capacity to exchange ADP bound in the tight catalytic site. It is suggested that the effects of DCCD, unlike those of Nbf-Cl, are closely related to the presence or absence of Mg2+.
傅里叶变换红外光谱（FT-IR）分析表明，在存在饱和浓度的ADP和AMP-PNP且不存在Mg2+的情况下，用抑制剂二环己基碳二亚胺（DCCD）和N-溴代琥珀酰亚胺（Nbf-Cl）处理F1ATP酶，不会改变该酶的二级结构，但会显著改变其紧密程度和热稳定性，不过程度有所不同。除了核苷酸诱导的稳定作用外，Nbf-Cl还会导致稳定性显著增加，而DCCD在这方面的效果较差。通过高效液相色谱（HPLC）测定在不存在Mg2+的情况下，用这两种抑制剂处理的F1ATP酶紧密结合核苷酸的交换速率，结果表明，在催化和非催化紧密位点，DCCD不会显著影响ADP与AMP-PNP的交换速率，反之亦然，而Nbf-Cl会选择性降低该酶在紧密催化位点交换结合ADP的能力。有人认为DCCD的作用与Nbf-Cl不同，它与Mg2+的存在与否密切相关。
