Nucleotide promiscuity of 3-phosphoglycerate kinase is in focus: implications for the design of better anti-HIV analogues
作者:Andrea Varga、Laurent Chaloin、Gyula Sági、Róbert Sendula、Éva Gráczer、Károly Liliom、Péter Závodszky、Corinne Lionne、Mária Vas
DOI:10.1039/c1mb05051f
日期:——
The wide specificity of 3-phosphoglycerate kinase (PGK) towards its nucleotide substrate is a property that allows contribution of this enzyme to the effective phosphorylation (i.e.activation) of nucleotide-based pro-drugs against HIV. Here, the structural basis of the nucleotide-PGK interaction is characterised in comparison to other kinases, namely pyruvate kinase (PK) and creatine kinase (CK), by enzyme kinetic analysis and structural modelling (docking) studies. The results provided evidence for favouring the purinevs.pyrimidine base containing nucleotides for PGK rather than for PK or CK. This is due to the exceptional ability of PGK in forming the hydrophobic contacts of the nucleotide rings that assures the appropriate positioning of the connected phosphate-chain for catalysis. As for the D-/L-configurations of the nucleotides, the L-forms (both purine and pyrimidine) are well accepted by PGK rather than either by PK or CK. Here again the dominance of the hydrophobic interactions of the L-form of pyrimidines with PGK is underlined in comparison with those of PK or CK. Furthermore, for the L-forms, the absence of the ribose OH-groups with PGK is better tolerated for the purine than for the pyrimidine containing compounds. On the other hand, the positioning of the phosphate-chain is an even more important term for PGK in the case of both purines and pyrimidines with an L-configuration, as deduced from the present kinetic studies with various nucleotide-site mutants of PGK. These characteristics of the kinase-nucleotide interactions can provide a guideline for designing new drugs.
3-磷酸甘油酸激酶(PGK)对其核苷酸底物的广泛特异性是一种特性,使得这种酶能够有效地磷酸化(即激活)基于核苷酸的抗HIV前药。在此,通过酶动力学分析和结构建模(对接)研究,与其它激酶(即丙酮酸激酶(PK)和肌酸激酶(CK))相比,对核苷酸-PGK相互作用的结构基础进行了表征。结果提供了证据,表明对于PGK来说,含有嘌呤与嘧啶的核苷酸更受青睐,而不是对于PK或CK。这是由于PGK在形成核苷酸环疏水接触方面的特殊能力,确保了连接的磷酸链在催化中的适当定位。至于核苷酸的D-/L-构型,L型(嘌呤和嘧啶)被PGK很好地接受,而不是由PK或CK接受。在这里,与PK或CK相比,嘧啶L型的疏水相互作用的支配性再次得到强调。此外,对于L型,PGK没有核糖OH基团的存在对嘌呤比对含有嘧啶的化合物更被接受。另一方面,从PGK的各种核苷酸位点突变体的当前动力学研究中推断出,无论是在嘌呤还是嘧啶的L型化合物中,磷酸链的定位对于PGK来说都是一个更为重要的术语。这些激酶-核苷酸相互作用的特性为设计新药物提供了指导。