Translational control of small heat shock genes in mesophilic and thermophilic cyanobacteria by RNA thermometers.

Cyanobacteria constitute a heterogeneous phylum of oxygen-producing, photosynthetic prokaryotes. They are susceptible to various stress conditions like heat, salt, or light stress, all inducing the cyanobacterial heat shock response (HSR). Cyanobacterial small heat shock proteins (sHsps) are known to preserve thylakoid membrane integrity under stress conditions, thereby protecting the photosynthesis machinery.

Thermogenetic tools to monitor temperature-dependent gene expression in bacteria.

Free-living bacteria constantly monitor their ambient temperature. Drastic deviations elicit immediate protective responses known as cold shock or heat shock response. Many mammalian pathogens use temperature surveillance systems to recognize the successful invasion of a host by its body temperature, usually 37°C.

Crystallization and preliminary crystallographic study of a ternary complex between the T4 phage beta-glucosyltransferase, uridine diphosphoglucose and a DNA fragment containing an abasic site.

A base-flipping phenomenon has been established for DNA methyltransferases and for DNA base-excision repair glycosylases and is likely to prove general for enzymes that need access to DNA bases to undergo chemical reaction. T4 phage beta-glucosyltransferase (BGT) is a good candidate for this novel mechanism. In order to confirm this, BGT was crystallized with an abasic site-containing DNA and uridine diphosphoglucose (UDP-glucose).

High resolution crystal structures of T4 phage beta-glucosyltransferase: induced fit and effect of substrate and metal binding.

beta-Glucosyltransferase (BGT) is a DNA-modifying enzyme encoded by bacteriophage T4 that transfers glucose from uridine diphosphoglucose to 5-hydroxymethyl cytosine bases of phage T4 DNA. We report six X-ray structures of the substrate-free and the UDP-bound enzyme. Four also contain metal ions which activate the enzyme, including Mg(2+) in forms 1 and 2 and Mn(2+) or Ca(2+).

T4 phage beta-glucosyltransferase: substrate binding and proposed catalytic mechanism.

beta-Glucosyltransferase (BGT) is a DNA-modifying enzyme encoded by bacteriophage T4 which catalyses the transfer of glucose (Glc) from uridine diphosphoglucose (UDP-Glc) to 5-hydroxymethylcytosine (5-HMC) in double-stranded DNA. The glucosylation of T4 phage DNA is part of a phage DNA protection system aimed at host nucleases. We previously reported the first three-dimensional structure of BGT determined from crystals grown in ammonium sulphate containing UDP-Glc.