(C) 2012 Elsevier Inc. All rights reserved.”
“pGEX vectors are widely used for GST-fusion protein expression in Escherichia selleck chemicals llc coli under the control of a strong IPTG inducible tac promoter. While using pGEX-4T-2 vector in heterologous protein expression we noticed that the GST or GST-fusion protein were expressed at a very low levels. Interestingly, we found a spontaneous deletion of 701 bp DNA fragment harbouring the tac promoter in both, native and recombinant pGEX-4T-2 vectors. This deletion took place
between two direct repeats of 43 bases and led to the loss of a 701 bp DNA fragment. This explained the decrease in GST or GST-fused protein level since the tac promoter, that directs transcription was deleted. The lacZ promoter, located upstream of the deleted fragment, replaced tac promoter but was less efficient. The deleted DNA also specifies part of the lacZ gene coding for the N-terminal end of the beta-galactosidase (the alpha-peptide), which is slightly functional. Consequently, bacterial cells transformed with the original pGEX are of a faint blue Caspase Inhibitor VI colour while those bearing the deleted ones are white,
when plated on X-Gal containing medium. The deletion, did not affect neither the sequence nor the molecular weight of GST and fusion protein since it took place just before the GST start codon. It occurred in E. coli TOP10 cells which are deficient in RecA protein, suggesting that the deletion did not require the RecA recombination system. (c) 2008 Elsevier Inc. All rights Carnitine palmitoyltransferase II reserved.”
“The ankyrin repeat (ANK) is the most common protein-protein interaction motif in nature, and is predominantly found in eukaryotic proteins. Genome sequencing
of various pathogenic or symbiotic bacteria and eukaryotic viruses has identified numerous genes encoding ANK-containing proteins that are proposed to have been acquired from eukaryotes by horizontal gene transfer. However, the recent discovery of additional ANK-containing proteins encoded in the genomes of archaea and free-living bacteria suggests either a more ancient origin of the ANK motif or multiple convergent evolution events. Many bacterial pathogens employ various types of secretion systems to deliver ANK-containing proteins into eukaryotic cells, where they mimic or manipulate various host functions. Studying the molecular and biochemical functions of this family of proteins will enhance our understanding of important host-microbe interactions.”
“Introduction: Pulmonary Langerhans cell histiocytosis (PLCH) is a rare cause of interstitial lung disease characterized by formation of nodules in the active phase of the disease that evolve into nonactive cystic lesions later on.