The crystal structure of PEP mutase from Mytilus edulis in complex with a substrate-analogue inhibitor, sulfopyruvate S-pyr (K(i) = 22 microM), has been determined at 2.25 A resolution. Mg(II)-S-pyr binds in the alpha/beta barrel's central channel, at the C-termini of the beta-strands. The binding mode of S-pyr's pyruvyl moiety resembles the binding mode of oxalate seen earlier. The location of...

The Escherichia coli BglF protein is a sugar permease that is a member of the phosphoenolpyruvate-dependent phosphotransferase system (PTS). It catalyses transport and phosphorylation of beta-glucosides. In addition to its ability to phosphorylate its sugar substrate, BglF has the unusual ability to phosphorylate and dephosphorylate the transcriptional regulator BglG according to beta-glucoside...

The Ser 3 Pro mutation in human nucleoside diphosphate kinase (NDK)-B/Nm23-H2 was recently found in melanoma cells. In comparison to the wild-type enzyme, steady state activity of NDK with ATP and TDP as substrates was slowed down 5-fold. We have utilized transient kinetic techniques to analyze phosphoryl transfer between the mutant enzyme and various pairs of nucleoside triphosphates and nucle...

The phosphoenolpyruvate:sugar phosphotransferase system (PTS) plays a key role in sugar uptake and metabolic regulation in bacteria. PTS proteins form a divergent phosphorylation cascade. Enzyme I (EI) is at the top of the cascade and mediates phosphoryl-transfer from phosphoenolpyruvate to the phosphoryl-carrier protein HPr, which then distributes the phosphoryl-groups to the different carbohy...

A series of monoclonal antibodies directed against lipid A was characterized by using synthetic lipid A analogs and partial structures. These compounds vary in phosphate substitution, acylation pattern (type, number, and distribution of fatty acids), and, in the case of monosaccharides, in their backbone glycosyl residue. The monoclonal antibodies tested could be subdivided into five groups acc...

Comparative kinetic and structural analyses of a variety of polymerases have revealed both common and divergent elements of nucleotide discrimination. Although the parameters for dNTP incorporation by the hyperthermophilic archaeal Family B Vent DNA polymerase are similar to those previously derived for Family A and B DNA polymerases, parameters for analog incorporation reveal alternative strat...

Histidine-aspartate phosphorelays are employed by two-component signal transduction family proteins to mediate responses to specific signals or stimuli in microorganisms and plants. The RedCDEF proteins constitute a novel signaling system in which four two-component proteins comprising a histidine kinase, a histidine-kinase like protein, and two response regulators function together to regulate...

Arginine residues are commonly found in the active sites of enzymes catalyzing phosphoryl transfer reactions. Numerous site-directed mutagenesis experiments establish the importance of these residues for efficient catalysis, but their role in catalysis is not clear. To examine the role of arginine residues in the phosphoryl transfer reaction, we have measured the consequences of mutations to ar...

The active site of multisubunit RNA polymerases (RNAPs) is highly conserved from humans to bacteria. This single site catalyzes both nucleotide addition required for RNA transcript synthesis and excision of incorrect nucleotides after misincorporation as a proofreading mechanism. Phosphoryl transfer and proofreading hydrolysis are controlled in part by a dynamic RNAP component called the trigge...

The molecular basis of many forms of signal transfer in living organisms is provided via the transient phosphorylation of regulatory proteins by transfer of phosphoryl groups between these proteins. The dominant form of signal transduction in prokaryotic microorganisms proceeds via so-called two-component regulatory systems. These systems constitute phosphoryl transfer pathways, consisting of t...