Using a cross-linking approach, we have analyzed the function of Skp, a presumed molecular chaperone of the periplasmic space of Escherichia coli, during the biogenesis of an outer membrane protein (OmpA). Following its transmembrane translocation, OmpA interacts with Skp in close vicinity to the plasma membrane. In vitro, Skp was also found to bind strongly and specifically to pOmpA nascent ch...

Acinetobacter baumannii strains resistant to all beta-lactams, aminoglycosides, and fluoroquinolones have emerged in many medical centers. Potential mechanisms contributing to antimicrobial resistance were investigated in 40 clinical isolates endemic to New York City. The isolates were examined for the presence of various beta-lactamases, aminoglycoside-modifying enzymes, and mutations in gyrA ...

Sequences of the major outer membrane protein (MOMP) gene (ompA) and the outer membrane complex B protein gene (omcB) from Chlamydia trachomatis, Chlamydia pneumoniae, and Chlamydia psittaci were analyzed for evidence of intragenic recombination and for linkage equilibrium. The Sawyer runs test, compatibility matrices, and index of association analyses provided substantial evidence that there h...

Outer membrane protein A (OmpA) is a conserved major component of the outer membrane of Enterobacteriaceae. Here, we report that OmpA from Klebsiella pneumoniae (KpOmpA) activates macrophages and dendritic cells (DCs) in a TLR2-dependent way. However, TLR2 does not account for binding of KpOmpA to innate immune cells. KpOmpA binds the scavenger receptors (SRs) LOX-1 and SREC-I, but not other me...

A retrospective analysis by molecular-sequence-based techniques was performed to correctly identify the etiological agent of 24 Mediterranean spotted fever cases occurring in Western Sicily, Italy, from 1987 to 2001. Restriction analysis of a 632-bp PCR-amplified portion of the ompA gene allowed presumptive identification of five clinical isolates as belonging to Rickettsia conorii subsp. israe...

Gram-negative bacteria such as Escherichia coli are protected by a complex cell envelope. The development of novel therapeutics against these bacteria necessitates a molecular level understanding of the structure-dynamics-function relationships of the various components of the cell envelope. We use atomistic MD simulations to reveal the details of covalent and noncovalent protein interactions t...

Neonatal meningitis by Eschericia coli RS218 occurs due to bacteremia and its transmigration across the blood-brain barrier. Although the outer membrane protein A (OmpA), a molecule with extracellular loops has been shown to contribute to the above phenomenon, we do not know the exact the role of these individual loops. Using bacterial strains whose individual loops have been removed, we demons...

The aim of this study was to investigate sequence-based genotyping methods to distinguish 27 Riemerella anatipestifer isolates from ducklings in South Korea. The 16S rRNA sequences of the 27 R. anatipestifer isolates showed 99�100% similarities to each other and to reference sequences from Genbank (AY871822.2, AY871834.2, CP002562.1, EU715016.1, EU016548.1, EU715000.1, EU715008.1 and EU715011.1...

The cell envelope protects bacteria from their surroundings. Defects in its integrity or assembly are sensed by signal transduction systems, allowing cells to rapidly adjust. The Rcs phosphorelay responds to outer membrane (OM)- and peptidoglycan-related stress in enterobacteria. We elucidated how the OM lipoprotein RcsF, the upstream Rcs component, senses envelope stress and activates the sign...

Molecular dynamics (MD) simulations are used to explore the dynamics of a membrane protein in its crystal environment. A 50-ns-duration simulation (at a temperature of 300 K) is performed for the crystallographic unit cell of the bacterial outer membrane protein OmpA. The unit cell contains four protein molecules, plus detergent molecules and water. An excellent correlation between simulated an...