Proline rich macrocyclic peptides (PRMPs) from marine sponges
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ABSTRACT: The mass spec data for PRMPs detected in marine sponges is deposited. Also the data differentiating leucine and isoleucine residues in cyclic peptides is deposited.
INSTRUMENT(S): Bruker ImpactII ultra-high-resolution Qq-ToF
Project description:This dataset consists of Spec-seq samples data for four tandem zinc finger proteins in human genome, each with two replicates. The Spec-seq is a medium throughput technique to characterize the binding specificity of a TF of interest to thousands of binding sites with resolution down to 0.2kT. Similar samples were deposited to NCBI GEO database before (GSE188166). The data analysis workflow for each ZFP can be accessed through https://github.com/zeropin/ZFPCookbook.
Project description:PepSAVI-MS, a mass spectrometry-based peptidomics pipeline, was implemented for antimicrobial peptide (AMP) discovery in the medicinal plant Amaranthus tricolor. This investigation revealed a novel 1.7 kDa AMP, deemed Atr-AMP1. Initial efforts to determine the sequence of Atr-AMP1 utilized chemical derivatization and enzymatic digestion to provide information about specific residues and post-translational modifications. EThcD (electron-transfer/higher-energy collision dissociation) produced extensive backbone fragmentation and facilitated de novo sequencing, the results of which were consistent with orthogonal characterization experiments. Additionally, multistage HCD (higher-energy collisional dissociation) facilitated discrimination between isobaric leucine and isoleucine. These results revealed a positively-charged proline-rich peptide present in a heterogeneous population of multiple peptidoforms, possessing several post-translational modifications including a disulfide bond, methionine oxidation, and proline hydroxylation.
Project description:A novel mass spectrometric method for discriminating isoleucine and leucine by MS3. The dimethylation of peptide N-termini leads to intense a1 ions in CID and MS3 fragmentation of the isoleucine/leucine a1-ion leads to spectra with fragments that can discriminate between the two isomers. The method was applied to two antibodies in combination with a set of protease treatments using trypsin, thermolysin, chymotrypsin and pepsin to generate peptides exposing N-terminal I/L residues.
Project description:For the first time in Lactococcus lactis, amino acid starvation response was characterized. The natural imposition of isoleucine starvation, by its consumption during growth, associated to transcript profiling, allowed defining exhaustively this stress stimulon. It consisted of a general induction of nitrogen metabolism (amino acid biosynthesis and transport, proteolytic system and proteases), a strong repression of genes encoding major physiological activities (translation, transcription, carbon metabolism, purine and pyrimidine biosynthesis and fatty acid metabolism) and the induction of unexpected cross responses to acid, osmotic and oxidative stresses. Keywords: stress response, time course Isoleucine starvation was imposed by the consumption of this amino acid during the growth of Lactococcus lactis IL1403 on ILV0.1 medium (CDM with ten-fold reduced concentrations of isoleucine, leucine and valine) and under controlled conditions (30 °C, pH 6.6, nitrogen atmosphere). Cell samples were harvested in exponential phase and after 30 min, 1.7 h and 3.5 h of isoleucine starvation. Total RNA was extracted from these samples and radiolabelled cDNA were prepared and hybridized on nylon arrays. 2053 amplicons specific of Lactococcus lactis IL1403 genes were spotted twice on the array. The 4 time-points were analyzed simultaneously and 3 independent repetitions were performed.