and production and split-intein mediated ligation (SIML) of circular bacteriocins.

Circular bacteriocins are antimicrobial peptides produced by bacteria that after synthesis undergo a head-to-tail circularization. Compared to their linear counterparts, circular bacteriocins are, in general, very stable to temperature and pH changes and more resistant to proteolytic enzymes, being considered as one of the most promising groups of antimicrobial peptides for their potential biotechnological applications. Up to now, only a reduced number of circular bacteriocins have been identified and fully characterized, although many operons potentially coding for new circular bacteriocins have been recently found in the genomes of different bacterial species.

A hypoallergenic variant of Der p 1 as a candidate for mite allergy vaccines.

Background: Recombinant hypoallergens that display reduced allergenicity but retain T-cell reactivity represent promising candidates to improve the safety and efficacy of allergen-specific vaccines or immunotherapy.

Objective: The current study reports the immunologic characterization of a hypoallergenic variant of the major mite allergen Der p 1.

Methods: The recombinant proform of Der p 1 (ProDer p 1) was expressed in Escherichia coli (ProDer p 1 coli), purified and characterized at the level of its secondary structure, and IgE and T-cell reactivities.

Amino acid signaling in yeast: casein kinase I and the Ssy5 endoprotease are key determinants of endoproteolytic activation of the membrane-bound Stp1 transcription factor.

Saccharomyces cerevisiae cells possess a plasma membrane sensor able to detect the presence of extracellular amino acids and then to activate a signaling pathway leading to transcriptional induction of multiple genes, e.g., AGP1, encoding an amino acid permease.

K+ channel interactions detected by a genetic system optimized for systematic studies of membrane protein interactions.

Organization of proteins into complexes is crucial for many cellular functions. However, most proteomic approaches primarily detect protein interactions for soluble proteins but are less suitable for membrane-associated complexes. Here we describe a mating-based split ubiquitin system (mbSUS) for systematic identification of interactions between membrane proteins as well as between membrane and soluble proteins.

Homo- and hetero-oligomerization of ammonium transporter-1 NH4 uniporters.

In most organisms, high affinity ammonium uptake is catalyzed by members of the ammonium transporter family (AMT/MEP/Rh). A single point mutation (G458D) in the cytosolic C terminus of the plasma membrane transporter LeAMT1;1 from tomato leads to loss of function, although mutant and wild type proteins show similar localization when expressed in yeast or plant protoplasts. Co-expression of LeAMT1;1 and mutant in Xenopus oocytes inhibited ammonium transport in a dominant negative manner, suggesting homo-oligomerization.

Functional profiling of the Saccharomyces cerevisiae genome.

Determining the effect of gene deletion is a fundamental approach to understanding gene function. Conventional genetic screens exhibit biases, and genes contributing to a phenotype are often missed. We systematically constructed a nearly complete collection of gene-deletion mutants (96% of annotated open reading frames, or ORFs) of the yeast Saccharomyces cerevisiae.