PubMed · 996657
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A J Lessing. 1976. Oxygen transport.. https://pubmed.ncbi.nlm.nih.gov/996657/
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We have synthesized a series of novel analogs of 1, 3-bisphospho-D-glyceric acid, 1,3-BPG,3 and evaluated their binding to phosphoglycerate kinase, PGK (EC 2.7.2.3). Nonscissile methanephosphonic acids replace the two phosphate monoesters of 1, 3-BPG and lead to several stable, tight-binding mimics of this intermediate species in glycolysis. Multiple fluorine substitution for hydrogen in the alpha-methylene groups of the phosphonic acid 1, 3-BPG analogs markedly improves their binding to PGK as determined by NMR analysis. The best ligands bind some 50-100 times more strongly than does the substrate 3-phospho-D-glyceric acid and show a requirement for pKa3 to be generally below 6.0, while the presence of a beta-carbonyl group seems to be of secondary importance.
Several bisphosphonates were examined as inhibitors of yeast GPD (glyceraldehyde-3-phosphate dehydrogenase, EC 1.2.1.12) and PGK (phosphoglycerate kinase, EC 2.7.2.3). The phosphonomethyl analog of 2-deoxy-1,3-bisphosphoglycerate (i.e., 2-oxo-1,5-bisphosphonopentane, 2-oxo-PC5P) is a good inhibitor of PGK (Ki = 0.2 +/- 0.08 mM at pH 8.5, 27 degrees C) and a poor inhibitor of GPD (Ki = 20 +/- 1 mM, pH 8.5). The shorter, butane, analog (2-oxo-PC4P) binds more tightly to PGK (Ki = 84 +/- 6 microM), and about equally well to GPD, as does 2-oxo-PC5P. The 2-oxo-bisphosphonates bind to PGK more tightly (by approx. 4 kJ/mol) than do the corresponding non-carbonyl analogues (1,4-bisphosphonobutane and 1,5-bisphosphonopentane).
High-resolution 1H and 31P nuclear magnetic resonance spectroscopy has been used to investigate the binding of 2,3-diphosphoglycerate to human normal adult hemoglobin and the molecular interactions involved in the allosteric effect of the 2,3-diphosphoglycerate molecule on hemoglobin. Individual hydrogen ion NMR titration curves have been obtained for 22-26 histidyl residues of hemoglobin and for each phosphate group of 2,3-diphosphoglycerate with hemoglobin in both the deoxy and carbonmonoxy forms. The results indicate that 2,3-diphosphoglycerate binds to deoxyhemoglobin at the central cavity between the two beta chains and the binding involves the beta 2-histidyl residues. Moreover, the results suggest that the binding site of 2,3-diphosphoglycerate to carbonmonoxyhemoglobin contains the same (or at least some of the same) amino acid residues responsible for binding in the deoxy form. As a result of the specific interactions with 2,3-diphosphoglycerate, the beta 2-histidyl residues make a significant contribution to the alkaline Bohr effect under these experimental conditions (up to 0.5 proton/Hb tetramer). 2,3-Diphosphoglycerate also affects the individual hydrogen ion equilibria of several histidyl residues located away from the binding site on the surface of the hemoglobin molecule, and, possibly, in the heme pockets. These results give the first experimental demonstration that long-range electrostatic and/or conformational effects of the binding could play an important role in the allosteric effect of 2,3-diphosphoglycerate on hemoglobin.(ABSTRACT TRUNCATED AT 250 WORDS)