Importance of conserved residues of the serine protease autotransporter beta-domain in passenger domain processing and beta-barrel assembly.

Serine protease autotransporters of the family Enterobacteriaceae (SPATE) comprise a family of virulence proteins secreted by enteric Gram-negative bacteria via the autotransporter secretion pathway. A SPATE polypeptide contains a C-terminal translocator domain that inserts into the bacterial outer membrane as a beta-barrel structure and mediates secretion of the passenger domain to the extracellular environment. In the present study, we examined the role of conserved residues located in the SPATE beta-barrel-forming region in passenger domain secretion.

Toxins and secretion systems of Photorhabdus luminescens.

Photorhabdus luminescens is a nematode-symbiotic, gram negative, bioluminescent bacterium, belonging to the family of Enterobacteriaceae. Recent studies show the importance of this bacterium as an alternative source of insecticides, as well as an emerging human pathogen. Various toxins have been identified and characterized in this bacterium.

Intramolecular interactions between the protease and structural domains are important for the functions of serine protease autotransporters.

Autotransporter (AT) is a protein secretion pathway found in Gram-negative bacteria featuring a multidomain polypeptide with a signal sequence, a passenger domain, and a translocator domain. An AT subfamily named serine protease ATs of the family Enterobacteriaceae (SPATEs) is characterized by the presence of a conserved serine protease motif in the passenger domain which contributes to bacterial pathogenesis. The goal of the current study is to determine the importance of the passenger domain conserved residues in the SPATE proteolytic and adhesive functions using the temperature-sensitive hemagglutinin (Tsh) protein as our model.

Common themes and variations in serine protease autotransporters.

The serine protease autotransporters of the Enterobacteriaceae (SPATEs) represent a group of large-sized, multi-domain exoproteins found only in pathogenic enteric bacteria. These proteins contain a highly conserved channel-forming C-terminal domain, which functions together with YaeT/Omp85 to facilitate secretion of the passenger domain to the cell surface. The C-terminal domain also mediates autoproteolytic cleavage, which releases the passenger from the bacterial cell.

Genome-wide in silico mapping of the secretome in pathogenic Yersinia pestis KIM.

Uncovering the secretome of Yersinia pestis is a necessary measure to better understand the virulence of this plague-causing bacterium. Using bioinformatics methods, the components of all the secretion systems known to date in the Y. pestis KIM genome were mapped, including several systems identified by this study.

Identification of autotransporter proteins secreted by type V secretion systems in gram-negative bacteria.

Autotransporters belong to a group of virulence factors secreted by Gram-negative bacteria using a simple mechanism termed type V or autotransporter secretion. These large proteins have diverse virulence functions, and many are found to play relevant roles in bacterial infections. An autotransporter polypeptide is equipped with two translocator domains (signal peptide and beta-domain), which enable its own export across bacterial membranes.

Omptin proteins: an expanding family of outer membrane proteases in Gram-negative Enterobacteriaceae.

The Escherichia coli K-12 outer membrane protein OmpT is a prototype of a unique family of bacterial endopeptidases known as the omptins. This family includes OmpT and OmpP of E. coli, SopA of Shigella flexneri, PgtE of Salmonella enterica, and Pla of Yersinia pestis.

Identification and characterization of autotransporter proteins of Yersinia pestis KIM.

Yersinia pestis is a Gram-negative bacterium that causes plague. Currently, plague is considered a re-emerging infectious disease and Y. pestis a potential bioterrorism agent.

Quaternary structure of a SPATE autotransporter protein.

The temperature-sensitive hemagglutinin (Tsh) is a representative of the growing subfamily of secreted bacterial virulence factors, known as serine protease autotransporters of the Enterobacteriaceae (SPATEs). Expressed by avian and human pathogenic strains of Escherichia coli Tsh acts as a serine protease and an adhesin to erythrocytes, hemoglobin, and extracellular matrix proteins. Mature Tsh is comprised of a 106-kDa secreted domain (Tshs) and a 33-kDa outer membrane beta-domain (Tshbeta).

Role of the alpha-helical linker of the C-terminal translocator in the biogenesis of the serine protease subfamily of autotransporters.

Autotransporters are secreted virulence factors that comprise three domains: an N-terminal signal peptide, an internal passenger domain, and a C-terminal beta-domain. The mechanism of passenger translocation across the outer membrane remains undefined, with four models having been proposed: the "hairpin," the "threading," the "multimeric," and the "Omp85 (YaeT)" models. In an attempt to understand autotransporter biogenesis, we screened the sequences of the serine protease subfamily of autotransporters (SPATEs) for conserved features indicative of a common secretion mechanism.

Protein secretion in the absence of ATP: the autotransporter, two-partner secretion and chaperone/usher pathways of gram-negative bacteria (review).

Bacteria secrete a wide variety of proteins, many of which play important roles in virulence. In gram-negative bacteria, these proteins must cross the cytoplasmic or inner membrane, periplasm, and outer membrane to reach the cell surface. Gram-negative bacteria have evolved multiple pathways to allow protein secretion across their complex envelope.

Coronary artery calcium by digital cinefluoroscopy in patients with pain suggestive of an acute coronary syndrome.

Background: Detection of coronary calcium may be a useful noninvasive approach for detecting coronary artery disease (CAD) in subjects presenting to the emergency department with chest pain.

Hypothesis: We tried to assess the diagnostic value of coronary artery calcium (CAC) detection by digital cinefluoroscopy in patients with new-onset chest pain suggestive of an acute coronary syndrome.

Methods: In 97 consecutive patients (70 men, 27 women, mean standard deviation [SD] age 55 (11) and 60 (8) years, respectively), with new-onset chest pain suggestive of an acute coronary syndrome, nondiagnostic electrocardiogram, and normal initial creatine kinase (CK)-MB, digital cinefluoroscopy was performed for CAC detection.

Autotransporter and two-partner secretion: delivery of large-size virulence factors by gram-negative bacterial pathogens.

A number of protein secretion mechanisms have been identified in gram-negative pathogens. Many of these secretion systems are dependent upon the Sec translocase for protein export from the cytoplasm into the periplasm and then utilize other mechanisms for transport from the periplasm through the outer membrane. In this article, we review secretion similarities between autotransporter and two-partner secretion systems, and we report similarities between the autotransporter secretion mechanism with that of intimin/invasins.

Functional analysis of the Tsh autotransporter from an avian pathogenic Escherichia coli strain.

The temperature-sensitive hemagglutinin (Tsh) is an autotransporter protein secreted by avian-pathogenic Escherichia coli strains that colonize the respiratory tract and lead to airsacculitis, pericarditis, and colisepticemia. It is synthesized as a 140-kDa precursor protein, whose processing results in a 106-kDa passenger domain (Tshs) and a 33-kDa beta-domain (Tsh(beta)). The presence of a conserved 7-amino-acid serine protease motif within Tshs classifies the protein in a subfamily of autotransporters, known as serine protease autotransporters of the Enterobacteriaceae.

Coronary calcium detected by digital cinefluoroscopy and coronary artery disease in patients undergoing coronary arteriography: effects of age and sex.

Background: Coronary artery calcium, detected non-invasively, correlates well with angiographically documented coronary artery disease (CAD). This study was conducted to evaluate the diagnostic efficacy of coronary artery calcium detected by digital cinefluoroscopy for CAD and assess the effects of age and sex on it.

Methods: In 242 patients who underwent coronary angiography, coronary calcium status was determined and related to angiographic findings.

Bacterial outer membrane ushers contain distinct targeting and assembly domains for pilus biogenesis.

Biogenesis of a superfamily of surface structures by gram-negative bacteria requires the chaperone/usher pathway, a terminal branch of the general secretory pathway. In this pathway a periplasmic chaperone works together with an outer membrane usher to direct substrate folding, assembly, and secretion to the cell surface. We analyzed the structure and function of the PapC usher required for P pilus biogenesis by uropathogenic Escherichia coli.

Contribution of the sST elevation/T-wave normalization in Q-wave leads during routine, pre-discharge treadmill exercise test to patient management and risk stratification after acute myocardial infarction: a 2.5-year follow-up study.

Objectives: This study investigated whether ST-segment elevation and T-wave normalization (TWN) in Q-wave leads on pre-discharge exercise electrocardiogram (ECG) can contribute to patient management after a recent myocardial infarction (MI).

Background: The clinical relevance of these exercise ECG changes remains controversial despite accumulating evidence of their association with myocardial viability. Because discrepancies of previous studies may depend on patient selection, the value of these ST/T abnormalities in the thrombolytic era should be better defined.