Volume 9 Issue 8, August 2013

Integration of chemistry-based approaches into enzyme engineering provides a versatile strategy for biocatalyst development with the potential for improved performance and new catalytic activities. Application of this strategy led to the development of a whole-cell catalyst capable of converting olefins into cyclopropanes, synthetic intermediates used in the synthesis of more functionalized cycloalkanes and acyclic compounds.

Mass spectrometry advances in single-cell metabolomics enable the discovery of a new biological insight that is not accessible from population-level studies. A new study reveals that single baker's yeast cells provide sufficient material to study chemical and genetic inhibition of glycolysis and identifies metabolic subpopulations that would be invisible in bulk.

Drug design for voltage-gated ion channels has long been hampered by the absence of crystal structures and the challenge of achieving subtype selectivity. A combination of mutagenesis, electrophysiology and molecular modeling has led to the identification of a new side pocket binding site for the small molecule Psora-4 between the pore and the voltage-sensor domain of Kv1.5, offering opportunities to design allosteric ion channel modulators.

Bioorthogonal chemistry, facilitated by enzymatic incorporation of chemical reporters in vitro or in cells, permits selective labeling and visualization of proteins, nucleic acids and other biomolecules such as glycans and lipids and facilitates the interrogation of their cellular functions.

The exchange of a heme-ligating cysteine for a serine residue in an engineered P450 alters the redox potential of the enzyme, deactivating wild-type function and enabling efficient, NADPH-mediated carbene transfer in cells.

Carbenes have been postulated to take part in the catalytic cycle of several enzymes, but direct detection of these unstable compounds has been elusive. Spectroscopic and structural studies of pyruvate oxidase now identify a carbene-containing cofactor, calling for reinspection of existing enzyme mechanisms.

Fosfomycin inhibits cell wall formation by preventing MurA-mediated UDP-MurNAc synthesis, but resistance to this drug suggested another route to UDP-MurNAc might exist. Genetic and biochemical studies identify two genes that, with an unknown phosphatase, define a new MurNAc salvage pathway.

A previously designed enzyme used a reactive lysine to initiate cleavage of a carbon-carbon bond. Directed evolution of this construct now shows a drastic reorganization of the active site to use an alternative catalytic lysine and suggests considerations for future design efforts.

Thiophene compounds kill M. tuberculosis by inhibiting Pks13, demonstrating that the enzyme catalyzes a critical step in biosynthesis of mycolic acids in vivo.

A Kv1 channel inhibitor and potential therapeutic lead achieves selectivity by binding both the conserved central cavity and newly identified side pockets, which provide the key determinants for channel specificity.

A high-throughput chemical screen of primary human hepatocytes in combination with machine-learning algorithms for evaluation of imaging data identifies compounds that promote expansion of primary human hepatocytes and maturation from human iPS cells toward an adult-like hepatocyte phenotype.

Chemoenzymatic synthesis of glycopeptides enables the identification of glycan specificity of two broadly neutralizing antibodies against HIV-1.