Identification and recombinant expression of an antimicrobial peptide (cecropin B-like) from soybean pest .

Background: Insects can be found in numerous diverse environments, being exposed to pathogenic organisms like fungi and bacteria. Once these pathogens cross insect physical barriers, the innate immune system operates through cellular and humoral responses. Antimicrobial peptides are small molecules produced by immune signaling cascades that develop an important and generalist role in insect defenses against a variety of microorganisms.

Retinoic Acid Binding Leads to CRABP2 Rigidification and Dimerization.

Cellular retinoic acid-binding protein 2 (CRABP2) delivers retinoic acid (atRA) to retinoic acid receptors (RARs), allowing for the activation of specific gene transcription. The structural similarities between free and atRA-bound CRABP2 raise the questions of how atRA binding occurs and how the atRA:CRABP2 complex is recognized by downstream binding partners. Thus, to gain insights into these questions, we conducted a detailed atRA-CRABP2 interaction study using nuclear magnetic resonance spectroscopy.

Oligomeric transition and dynamics of RNA binding by the HuR RRM1 domain in solution.

Human antigen R (HuR) functions as a major post-transcriptional regulator of gene expression through its RNA-binding activity. HuR is composed by three RNA recognition motifs, namely RRM1, RRM2, and RRM3. The two N-terminal RRM domains are disposed in tandem and contribute mostly to HuR interaction with adenine and uracil-rich elements (ARE) in mRNA.

Refolding, purification, and preliminary structural characterization of the DNA-binding domain of the quorum sensing receptor RhlR from Pseudomonas aeruginosa.

RhlR is a 241-residue quorum sensing receptor that controls the expression of a myriad of virulence genes in Pseudomonas aeruginosa. Here, the DNA sequence encoding the carboxi-terminal DNA-binding domain of RhlR was cloned into the pET-RP1B plasmid and expressed as an N-terminal fusion protein to the expression/purification Thio6His6 tag. The fusion construct expressed insolubly in Escherichia coli BL21 (DE3) cells.

A structural perspective on the mechanisms of quorum sensing activation in bacteria.

Bacteria are able to synchronize the population behavior in order to regulate gene expression through a cell-to-cell communication mechanism called quorum sensing. This phenomenon involves the production, detection and the response to extracellular signaling molecules named autoinducers, which directly or indirectly regulate gene expression in a cell density-dependent manner. Quorum sensing may control a wide range of biological processes in bacteria, such as bioluminescence, virulence factor production, biofilm formation and antibiotic resistance.

(1)H, (15)N and (13)C resonance assignments of the RRM1 domain of the key post-transcriptional regulator HuR.

Human antigen R (HuR) is a ubiquitous protein that recognizes adenylate and uridylate-rich elements in mRNA, thereby interfering with the fate of protein translation. This protein plays a central role in the outcome of the inflammatory response as it may stabilize or silence mRNAs of key components of the immune system. HuR is able to interact with other RNA-binding proteins, reflecting a complex network that dictates mRNAs post-transcriptional control.