The allosteric regulation of pyruvate kinase

Abstract

Crystallographic and mutagenesis studies have unravelled the general features of the allosteric transition mechanism in pyruvate kinase. The enzyme displays a dramatic conformational change in going from the T-to the R-state. All three domains forming each subunit of the tetrameric enzyme undergo simultaneous and concerted rotations, in such a way that all subunit and domain interfaces are modified. This mechanism is unprecedented since in all tetrameric allosteric enzymes, characterised at atomic resolution, at least one of the domain or subunit interfaces remains unchanged on the T-to R-state transition. The molecular mechanism of allosteric regulation here proposed provides a rationale for the effect of single site mutations observed in the human erythrocyte pyruvate kinase associated with a congenital anaemia.Key words." Glycolysis; Metabolism regulation; X-ray crystallography; Pyruvate kinase whereas the L PK is additionally controlled by phosphorylation on a N-terminal Ser residue which causes a decrease in the affinity for the PEP and FBP activators [3]. More unusual is the muscle M1 protein [6] which is the only known PK displaying hyperbolic kinetics and no allosteric control.While the structure of the cat M1 isoenzyme was determined by Muirhead and coworkers several years ago [6], little information was available about the allosteric transition in PK. Substantial progress in this respect has been observed over the last few years with further refinement of the M1 isoenzyme model [7], and with the X-ray structure determination of the FBP-dependent E. coli PK, in the inactive T-state [8]. Furthermore, insight into the enzyme regulatory properties has been provided by mutagenesis studies [9] and by the characterisation of several R PK variants from patients with congenital anaemia [10].

Structure and Function of Human Erythrocyte Pyruvate Kinase

“…Rationale for the Mutagenesis Studies-A survey of the missense mutations associated with the nonspherocytic hemolytic anemia shows that most of them cluster in specific regions of the protein three-dimensional structure: the interface between the A and C domains, the A/AЈ intersubunit interface, the hydrophobic core of the A domain, and the FBP-binding site (24). We generated eight RPK mutants (Fig.…”

MicroRNA-7 Promotes Glycolysis to Protect against 1-Methyl-4-phenylpyridinium-induced Cell Death

“…Pyruvate kinase activity is allosterically regulated by fructose 1,6-bisphosphate, P-enolpyruvate, and ATP (18,19). Although fructose 1,6-bisphosphate and P-enolpyruvate increase pyruvate kinase activity (19,20), high ATP level decreases it (19). The glycolysispromoting effect of miR-7 leads to increase in fructose 1,6-bisphosphate, P-enolpyruvate, and ATP inside the cell.…”

Comparative Analysis of Pyruvate Kinases from the Hyperthermophilic Archaea Archaeoglobus fulgidus, Aeropyrum pernix, and Pyrobaculum aerophilum and the Hyperthermophilic Bacterium Thermotoga maritima

“…PKs are well characterized enzymes from many eukarya and bacteria (13)(14)(15). The PKs are usually homotetrameric enzymes of about 200 kDa composed of 50-kDa subunits; the enzymes require divalent cations for activity; many PKs were shown to be activated by monovalent cations, K ϩ or NH 4 ϩ .…”

“…Few nonallosteric PKs have also been described, e.g. M1 isoenzyme of vertebrates and the dimeric PKs from Schizosaccharomyces pombe and Zymomonas mobilis (15,21,22). More than 140 primary sequences of eukarya and bacteria are known.…”