Quantifying prion disease penetrance using large population control cohorts.

More than 100,000 genetic variants are reported to cause Mendelian disease in humans, but the penetrance-the probability that a carrier of the purported disease-causing genotype will indeed develop the disease-is generally unknown. We assess the impact of variants in the prion protein gene (PRNP) on the risk of prion disease by analyzing 16,025 prion disease cases, 60,706 population control exomes, and 531,575 individuals genotyped by 23andMe Inc. We show that missense variants in PRNP previously reported to be pathogenic are at least 30 times more common in the population than expected on the basis of genetic prion disease prevalence.

Functional conformations for pyruvate carboxylase during catalysis explored by cryoelectron microscopy.

The tetrameric enzyme pyruvate carboxylase (PC), a biotin-dependent carboxylase, produces oxaloacetate by two consecutive reactions that take place in distant active sites. Previous crystal structures revealed two different configurations for PC tetramers, the so-called symmetric and asymmetric, which were understood as characteristic molecular architectures for PC from different organisms. We have analyzed PC samples from Staphylococcus aureus while the enzyme generates oxaloacetate, expecting PC tetramers to display the conformational landscape relevant for its functioning.

Characterizing the importance of the biotin carboxylase domain dimer for Staphylococcus aureus pyruvate carboxylase catalysis.

Biotin carboxylase (BC) is a conserved component among biotin-dependent carboxylases and catalyzes the MgATP-dependent carboxylation of biotin, using bicarbonate as the CO₂ donor. Studies with Escherichia coli BC have suggested long-range communication between the two active sites of a dimer, although its mechanism is not well understood. In addition, mutations in the dimer interface can produce stable monomers that are still catalytically active.

Mechanism for the inhibition of the carboxyltransferase domain of acetyl-coenzyme A carboxylase by pinoxaden.

Acetyl-CoA carboxylases (ACCs) are crucial metabolic enzymes and have been targeted for drug development against obesity, diabetes, and other diseases. The carboxyltransferase (CT) domain of this enzyme is the site of action for three different classes of herbicides, as represented by haloxyfop, tepraloxydim, and pinoxaden. Our earlier studies have demonstrated that haloxyfop and tepraloxydim bind in the CT active site at the interface of its dimer.

Cryo-EM analysis reveals new insights into the mechanism of action of pyruvate carboxylase.

Pyruvate carboxylase (PC) is a conserved multifunctional enzyme linked to important metabolic diseases. PC homotetramer is arranged in two layers with two opposing monomers per layer. Cryo-EM explores the conformational variability of PC in the presence of different substrates.

A symmetrical tetramer for S. aureus pyruvate carboxylase in complex with coenzyme A.

Pyruvate carboxylase (PC) is a conserved metabolic enzyme with important cellular functions. We report crystallographic and cryo-electron microscopy (EM) studies of Staphylococcus aureus PC (SaPC) in complex with acetyl-CoA, an allosteric activator, and mutagenesis, biochemical, and structural studies of the biotin binding site of its carboxyltransferase (CT) domain. The disease-causing A610T mutation abolishes catalytic activity by blocking biotin binding to the CT active site, and Thr908 might play a catalytic role in the CT reaction.

Crystal structure of biotin carboxylase in complex with substrates and implications for its catalytic mechanism.

Biotin-dependent carboxylases are widely distributed in nature and have important functions in many cellular processes. These enzymes share a conserved biotin carboxylase (BC) component, which catalyzes the ATP-dependent carboxylation of biotin using bicarbonate as the donor. Despite the availability of a large amount of biochemical and structural information on BC, the molecular basis for its catalysis is currently still poorly understood.