Optimizing SureQuant for Targeted Peptide Quantification: a Technical Comparison with PRM and SWATH-MS Methods.

Bacterial infections are a major threat to human health worldwide. A better understanding of the properties and physiology of bacterial pathogens in human tissues is required to develop urgently needed novel control strategies. Mass spectrometry-based proteomics could yield such data, but identifying and quantifying scarce bacterial proteins against a preponderance of human proteins is challenging.

Sample Preparation for Mass Spectrometry-Based Absolute Quantification of Bacterial Proteins in Antibiotic Stress Research.

Absolute protein quantification is an essential tool for system biology approaches and elucidation of stoichiometry of multi-protein complexes. In this updated chapter, a universal protocol for gel-free absolute protein quantification in bacterial systems is described, which provides adapted methods for cytosolic and membrane proteins. This protocol can be used for sample preparation prior to miscellaneous mass spectrometry-based quantification workflows like AQUA, Hi3, and emPAI.

The Emerging Potential of Advanced Targeted Mass Spectrometry to Become a Routine Tool for Protein Quantification in Biomedical Research.

Mass spectrometry-based proteomics has become an indispensable tool for system-wide protein quantification in systems biology, biomedical research, and increasing for clinical applications. In particular, targeted mass spectrometry offers the most sensitive and reproducible quantitative detection of proteins, peptides and post-translational modifications of any currently applied mass spectrometry technique and is therefore ideally suited to generate high quality quantitative datasets. Despite these apparent advantages, targeted mass spectrometry is only slowly gaining popularity in academia and pharmaceutical industries, mainly due to the additional efforts in assay generation and manual data validation.

Redirected Stress Responses in a Genome-Minimized 'midi' Strain with Enhanced Capacity for Protein Secretion.

Genome engineering offers the possibility to create completely novel cell factories with enhanced properties for biotechnological applications. In recent years, genome minimization was extensively explored in the Gram-positive bacterial cell factory Bacillus subtilis, where up to 42% of the genome encoding dispensable functions was removed. Such studies showed that some strains with minimized genomes gained beneficial features, especially for secretory protein production.

Molecular reprogramming and phenotype switching in lead to high antibiotic persistence and affect therapy success.

causes invasive infections and easily acquires antibiotic resistance. Even antibiotic-susceptible can survive antibiotic therapy and persist, requiring prolonged treatment and surgical interventions. These so-called persisters display an arrested-growth phenotype, tolerate high antibiotic concentrations, and are associated with chronic and recurrent infections.

SppI Forms a Membrane Protein Complex with SppA and Inhibits Its Protease Activity in Bacillus subtilis.

The membrane protease SppA of was first described as a signal peptide peptidase and later shown to confer resistance to lantibiotics. Here, we report that SppA forms octameric complexes with YteJ, a membrane protein of thus-far-unknown function. Interestingly, and deletion mutants exhibited no protein secretion defects.

Functional association of the stress-responsive LiaH protein and the minimal TatAyCy protein translocase in Bacillus subtilis.

The bacterial twin-arginine (Tat) pathway serves in the exclusive secretion of folded proteins with bound cofactors. While Tat pathways in Gram-negative bacteria and chloroplast thylakoids consist of conserved TatA, TatB and TatC subunits, the Tat pathways of Bacillus species and many other Gram-positive bacteria stand out for their minimalist nature with the core translocase being composed of essential TatA and TatC subunits only. Here we addressed the question whether the minimal TatAyCy translocase of Bacillus subtilis recruits additional cellular components that modulate its activity.

Membrane Modulation of Super-Secreting "midi" Expressing the Major Antigen - A Mass-Spectrometry-Based Absolute Quantification Approach.

has been extensively used as a microbial cell factory for industrial enzymes due to its excellent capacities for protein secretion and large-scale fermentation. This bacterium is also an attractive host for biopharmaceutical production. However, the secretion potential of this organism is not fully utilized yet, mostly due to a limited understanding of critical rearrangements in the membrane proteome upon high-level protein secretion.

Can Adapt Its Protein Translocation Machinery for Enhanced Periplasmic Recombinant Protein Production.

Recently, we engineered a tunable rhamnose promoter-based setup for the production of recombinant proteins in . This setup enabled us to show that being able to precisely set the production rate of a secretory recombinant protein is critical to enhance protein production yields in the periplasm. It is assumed that precisely setting the production rate of a secretory recombinant protein is required to harmonize its production rate with the protein translocation capacity of the cell.

Identification and optimization of PrsA in Bacillus subtilis for improved yield of amylase.

Background: PrsA is an extracytoplasmic folding catalyst essential in Bacillus subtilis. Overexpression of the native PrsA from B. subtilis has repeatedly lead to increased amylase yields.

Ariadne's Thread in the Analytical Labyrinth of Membrane Proteins: Integration of Targeted and Shotgun Proteomics for Global Absolute Quantification of Membrane Proteins.

The field of systems biology has been rapidly developing in the past decade. However, the data produced by "omics" approaches is lagging behind the requirements of this field, especially when it comes to absolute abundances of membrane proteins. In the present study, a novel approach for large-scale absolute quantification of this challenging subset of proteins has been established and evaluated using osmotic stress management in the Gram-positive model bacterium as proof-of-principle precedent.