In vitro, polynucleotide phosphorylase of Escherichia coli can both synthesize RNA by using nucleotide diphosphates as precursors and exonucleolytically degrade RNA in the presence of inorganic phosphate. However, because of the high in vivo concentration of inorganic phosphate in exponentially growing cells, it has been assumed that the enzyme works exclusively as an exonuclease. Here we demon...

Maturation of tRNA precursors into functional tRNA molecules requires trimming of the primary transcript at both the 5’ and 3’ ends. Cleavage of nucleotides from the 3’ stem of tRNA precursors, releasing nucleotide diphosphates, is accomplished in Bacillus by a phosphate dependent exoribonuclease, Rph. The crystal structure of this enzyme from Bacillus anthracis has been solved by molecular rep...

The RNA exosome is a multisubunit exonuclease involved in numerous RNA maturation and degradation processes. Exosomes are found in eukaryotes and archaea and are related to bacterial polynucleotide phosphorylates. Over the past years structural and biochemical analysis revealed that archaeal exosomes have a large processing chamber with three phosphorolytic active sites that degrade RNA in the ...

sence of exogenously added glutamate and pyridoxal-5'-phosphate and produced radioactive aspartate in the presence of these components. Reduced nicotinamide adenine dinucleotide or reduced nicotinamide adenine dinucleotide phosphate could not be substituted for adenosine triphosphate (ATP); phosphoenolpyruvate even in the presence of nucleoside diphosphates could not replace pyruvate plus ATP; ...

Katheryn Adam, Chemistry Faculty Mentor: Marco Bonizzoni, Chemistry An off-the-shelf sensing system for physiologically relevant phosphates We have developed a chemical sensing system that can differentiate biologically relevant phosphates (nucleoside diphosphates, pyrophosphate) in neutral water solution using only commercially available components. Our approach uses a common fluorescent indic...

Nature routinely engages alcohols as leaving groups, as DNA biosynthesis relies on the removal of water from ribonucleoside diphosphates by a radical-mediated "spin-center shift" (SCS) mechanism. Alcohols, however, remain underused as alkylating agents in synthetic chemistry due to their low reactivity in two-electron pathways. We report herein an enantioselective α-benzylation of aldehydes usi...

Polynucleotide phosphorylase (PNPase), an enzyme conserved in bacteria and eukaryotic organelles, processively catalyzes the phosphorolysis of RNA, releasing nucleotide diphosphates, and the reverse polymerization reaction. In Escherichia coli, both reactions are implicated in RNA decay, as addition of either poly(A) or heteropolymeric tails targets RNA to degradation. PNPase may also be associ...

Polynucleotide phosphorylase (PNPase), an enzyme conserved in Bacteria and eukaryotic organelles, processively catalyzes the phosphorolysis of RNA releasing nucleotide diphosphates and the reverse polymerization reaction. In E. coli both reactions are implicated in RNA decay, as addition of either poly(A) or heteropolymeric tails targets RNA to degradation. PNPase may also be associated with th...

Different forms of energy are interconverted in biological systems. For this purpose, the cell uses phosphate compounds as the common currency of energy exchange [1]. The hydrolysis of these compounds is catalyzed by enzymes that are capable of energy transduction. These enzymes use the chemical energy derived from the cleavage of phosphate compounds such as ATP, acetyl phosphate and pyrophosph...

Pyrophosphate analogues are of great importance especially for the design of biologically active molecules. The phospha-Claisen condensation allows for the rapid synthesis of (phosphonomethyl)phosphinate pyrophosphate analogues and building blocks that can be employed in numerous applications.