Volume 12 Issue 3, March 2016

The versatility of RNA is achieved in part through its ability to adopt various shapes of structures. A new technology called X-ray scattering interferometry enables the detection of 'invisible' states by lighting up gold pairs tagged to RNA molecules.

The arrest peptides that function with the macrolide antibiotic erythromycin stall translating ribosomes in the presence of the antibiotic, leading to remodeling of the downstream mRNA and enhancement of the translation of resistance genes. Current work suggests that small changes in the nascent peptide dictate the ability of ribosomes to respond to this and other small molecules.

Bioorthogonal chemistry approaches have traditionally focused on selective ligation reactions between compatible reactive groups. This Perspective highlights progress in developing bioorthogonal cleavage reactions for diverse applications in chemical biology.

Expansion of the genetic code to noncanonical amino acids (NCAAs) has been limited by the lack of evolutionary pressure for organismal dependence on the NCAA. Linking bacterial survival to an engineered β-lactamase that requires a non-natural tyrosine analog engenders diverse bacteria with a stable, expanded genetic code.

The protonation state of Glu14 within the drug transporter EmrE is able to influence the conformational dynamics of the protein and thereby bias the inward-open conformation to facilitate substrate efflux.

XSI analysis of two RNA kink-turn motifs, KtA and KtB, in a range of solution concentrations and in the presence of the kink-turn protein partner L7Ae reveals a restricted conformational ensemble that is regulated by ions and protein binding.

Point mutations in nascent peptides that regulate in the macrolide antibiotic resistance genes ermC and ermB can tune the recognition of the antibiotics erythromycin and telithromycin that control ribosome stalling and gene activation.

Oscillations of actin, FBP17 and N-WASP are coupled to phase-shifted phosphoinositide (PI) turnover that is regulated by the lipid phosphatases SHIP1, synaptojanin 2 and PI 3-kinases. PI(4,5)P₂ turnover regulates wave amplitude and PI(3,4)P₂ acts as a pacemaker.

A scan of the protein structure database looking for interhelical contacts across transmembrane protein helix trimers finds six distinct structural and topological classes with unique sequence-3D contact motifs that could prove useful in future protein design initiatives.

The antifungal drug naftifine blocks carotenoid pigment biosynthesis in Staphylococcus aureus through inhibition of a biosynthetic enzyme of staphyloxanthin, disabling an important virulence mechanism and thus making the pathogen susceptible to host oxidant killing.

Chromodomains in chromatin-associated proteins act as ‘readers’ of methylated lysines within histones. Structural and computational design led to the identification of UNC3866, a potent, cell-active peptide-based inhibitor of the methyllysine reading functions of CBX and CDY chromodomains.

Suv39h1 is a histone methyltransferase that methylates H3K9 residues in heterochromatic regions of the genome. An approach using semisynthetic chromatin reveals a mechanism for heterochromatin spreading in which H3K9 trimethylation anchors and activates Suv39h1 for modification of proximal lysines.

Pyridoxal 5-phosphate (PLP) is an essential coenzyme involved in diverse amino acid transformations. The discovery that Ind4 catalyzes the PLP-dependent oxidation of an unactivated carbon of L-arginine, as a part of the indolmycin biosynthetic pathway, expands the scope of reactions facilitated by PLP-dependent enzymes.