Nucleic acid joining enzymes: biological functions and synthetic applications beyond DNA.

DNA-joining by ligase and polymerase enzymes has provided the foundational tools for generating recombinant DNA and enabled the assembly of gene and genome-sized synthetic products. Xenobiotic nucleic acid (XNA) analogues of DNA and RNA with alternatives to the canonical bases, so-called 'unnatural' nucleobase pairs (UBP-XNAs), represent the next frontier of nucleic acid technologies, with applications as novel therapeutics and in engineering semi-synthetic biological organisms. To realise the full potential of UBP-XNAs, researchers require a suite of compatible enzymes for processing nucleic acids on a par with those already available for manipulating canonical DNA.

In vivo simultaneous proton resonance frequency shift thermometry and single reference variable flip angle T measurements.

Purpose: The single reference variable flip angle sequence with a multi-echo stack of stars acquisition (SR-VFA-SoS) simultaneously measures temperature change using proton resonance frequency (PRF) shift and T-based thermometry methods. This work evaluates SR-VFA-SoS thermometry in MR-guided focused ultrasound in an in vivo rabbit model.

Methods: Simultaneous PRF shift thermometry and T-based thermometry were obtained in a New Zealand white rabbit model (n = 7) during MR-guided focused ultrasound surgery using the SR-VFA-SoS sequence at 3 T.

3D variability analysis reveals a hidden conformational change controlling ammonia transport in human asparagine synthetase.

Advances in X-ray crystallography and cryogenic electron microscopy (cryo-EM) offer the promise of elucidating functionally relevant conformational changes that are not easily studied by other biophysical methods. Here we show that 3D variability analysis (3DVA) of the cryo-EM map for wild-type (WT) human asparagine synthetase (ASNS) identifies a functional role for the Arg-142 side chain and test this hypothesis experimentally by characterizing the R142I variant in which Arg-142 is replaced by isoleucine. Support for Arg-142 playing a role in the intramolecular translocation of ammonia between the active site of the enzyme is provided by the glutamine-dependent synthetase activity of the R142 variant relative to WT ASNS, and MD simulations provide a possible molecular mechanism for these findings.

Fat extraction methodology can affect the food fatty acid profile: Improvement of a protocol more environmentally friendly.

Fatty acids (FAs) are biochemical components of food, essential for human health due to their numerous biological functions. However, many of then if consumed in excess can trigger disfunctions/illness. Therefore, analytical methods, such as gas chromatography (GC-FID) are essential for the accurate identification and quantification of FAs, playing an important role in food safety and quality assessment.