Search results for "Periplasm"
showing 10 items of 32 documents
Relative Abundances of Proteobacterial Membrane-Bound and Periplasmic Nitrate Reductases in Selected Environments
2007
ABSTRACT Dissimilatory nitrate reduction is catalyzed by a membrane-bound and a periplasmic nitrate reductase. We set up a real-time PCR assay to quantify these two enzymes, using the narG and napA genes, encoding the catalytic subunits of the two types of nitrate reductases, as molecular markers. The narG and napA gene copy numbers in DNA extracted from 18 different environments showed high variations, with most numbers ranging from 2 × 10 2 to 6.8 × 10 4 copies per ng of DNA. This study provides evidence that, in soil samples, the number of proteobacteria carrying the napA gene is often as high as that of proteobacteria carrying the narG gene. The high correlation observed between narG an…
Construction of an agglutination tool: recombinant Fab fragments biotinylated in vitro.
2009
The pComb3H vector system is used for constructing and panning recombinant antibody libraries. It allows for expression of monovalent Fab fragments, either on the surface of M13 phage, or in the form of soluble proteins secreted into the periplasmic space of bacteria. We constructed a modified pComb3H vector containing cDNA encoding for a 23-amino acid fragment of the Escherichia coli biotin carboxy carrier protein (BCCP), which is an acceptor sequence for biotinylation. The vector was used to express the Fab fragment recognizing human glycophorin A. The purified Fab fragment containing this biotin acceptor sequence was effectively biotinylated in vitro using biotin ligase (BirA). The speci…
Phospholipid distribution in the cytoplasmic membrane of Gram-negative bacteria is highly asymmetric, dynamic, and cell shape-dependent
2020
The cell shape of Gram-negative bacteria is maintained metabolically by asymmetric lipid distribution in biogenic plasma membrane.
The role of Components of the Outer Membrane of Gram-Negative Bacteria in the Serum-Bactericidal Effect
1982
Abstract Effective killing-capacity of normal human and guinea pig sera depended on Ca ++ , C1q, C2 and C4. Fixation- and transfer-tests revealed that C1 and C1q were bound more tightly to the serum-sensitive R-forms of Salmonella strains than to the serum-resistant S-forms. Since all experiments were done in the absence of antibodies these findings provide evidence that the antibody-independent C1-binding is one of the initial reactions of the serum-mediated killing. This reaction seems to be influenced by the sugar-portion of the lipopolysaccharide (LPs) of the outer membrane: C1-binding to the bacteria occurs with higher affinity the shorter the LPS-molecule. This indicates that other ou…
Fumarate regulation of gene expression in Escherichia coli by the DcuSR (dcuSR genes) two-component regulatory system.
1998
ABSTRACT In Escherichia coli the genes encoding the anaerobic fumarate respiratory system are transcriptionally regulated by C 4 -dicarboxylates. The regulation is effected by a two-component regulatory system, DcuSR, consisting of a sensory histidine kinase (DcuS) and a response regulator (DcuR). DcuS and DcuR are encoded by the dcuSR genes (previously yjdHG ) at 93.7 min on the calculated E. coli map. Inactivation of the dcuR and dcuS genes caused the loss of C 4 -dicarboxylate-stimulated synthesis of fumarate reductase ( frdABCD genes) and of the anaerobic fumarate-succinate antiporter DcuB ( dcuB gene). DcuS is predicted to contain a large periplasmic domain as the supposed site for C 4…
Evolutionary Dissection of the Dot/Icm System Based on Comparative Genomics of 58 Legionella Species
2019
14 páginas, 2 figuras, 2 tablas
Metabolism of Saccharomyces cerevisiae envelope mannoproteins.
1982
By pulse and chase labeling experiments, two independent mannoprotein pools have been found associated with the Saccharomyces cerevisiae envelope. One of them probably corresponds to mannoproteins localized in the periplasmic space. These molecules showed a high turnover rate at 28 degrees C. The second pool is formed by intrinsic wall mannoproteins which are apparently stable for long periods of time, after a small initial turnover. These results suggest that at least part of the mannoproteins initially found in the periplasmic space may move into the wall. The time lag between the addition of the radioactive precursors and their incorporation in the cell envelope (20-30 min for amino acid…
Distant downstream sequence determinants can control N-tail translocation during protein insertion into the endoplasmic reticulum membrane.
2000
We have studied the membrane insertion of ProW, an Escherichia coli inner membrane protein with seven transmembrane segments and a large periplasmic N-terminal tail, into endoplasmic reticulum (ER)-derived dog pancreas microsomes. Strikingly, significant levels of N-tail translocation is seen only when a minimum of four of the transmembrane segments are present; for constructs with fewer transmembrane segments, the N-tail remains mostly nontranslocated and the majority of the molecules adopt an 'inverted' topology where normally nontranslocated parts are translocated and vice versa. N-tail translocation can also be promoted by shortening of the N-tail and by the addition of positively charg…
Crystal structure of the N-terminal domain of the major virulence factor BB0323 from the Lyme disease agent Borrelia burgdorferi.
2019
Lyme disease is an infection caused by the spirochete Borrelia burgdorferi after it is transmitted to a mammalian organism during a tick blood meal. B. burgdorferi encodes at least 140 lipoproteins located on the outer or inner membrane, thus facing the surroundings or the periplasmic space, respectively. However, most of the predicted lipoproteins are of unknown function, and only a few proteins are known to be essential for the persistence and virulence of the pathogen. One such protein is the periplasmic BB0323, which is indispensable for B. burgdorferi to cause Lyme disease and the function of which is associated with cell fission and outer membrane integrity. After expression and trans…
The NMR structure of the sensory domain of the membranous two-component fumarate sensor (histidine protein kinase) DcuS of Escherichia coli
2003
The structure of the water-soluble, periplasmic domain of the fumarate sensor DcuS (DcuS-pd) has been determined by NMR spectroscopy in solution. DcuS is a prototype for a sensory histidine kinase with transmembrane signal transfer. DcuS belongs to the CitA family of sensors that are specific for sensing di- and tricarboxylates. The periplasmic domain is folded autonomously and shows helices at the N and the C terminus, suggesting direct linking or connection to helices in the two transmembrane regions. The structure constitutes a novel fold. The nearest structural neighbor is the Per-Arnt-Sim domain of the photoactive yellow protein that binds small molecules covalently. Residues Arg107, H…