Seca
Mostrando 1-12 de 14877 artigos, teses e dissertações.
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1. Isolation and analysis of dominant secA mutations in Escherichia coli.
The secA gene product is an autoregulated, membrane-associated ATPase which catalyzes protein export across the Escherichia coli plasma membrane. Previous genetic selective strategies have yielded secA mutations at a limited number of sites. In order to define additional regions of the SecA protein that are important in its biological function, we mutagenize
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2. SecA protein is required for translocation of a model precursor protein into inverted vesicles of Escherichia coli plasma membrane.
We have investigated whether the SecA protein is required for in vitro translocation of a model presecretory protein into inverted vesicles (INV) of the Escherichia coli plasma membrane. Contrary to previous reports, we found that urea-extracted INV that contained only the membrane-integral form of SecA were fully translocation active. Proteoliposomes that w
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3. Site-specific proteolysis of the Escherichia coli SecA protein in vivo.
A seven-amino-acid cleavage site specific for tobacco etch virus (TEV) protease was introduced into SecA at two separate positions after amino acids 195 and 252. Chromosomal wild-type secA was replaced by these secA constructs. Simultaneous expression of TEV protease led to cleavage of both SecA derivatives. In the functional SecA dimer, proteolysis directly
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4. Multiple SecA protein isoforms in Escherichia coli.
To define the anti-SecA-LacZ antiserum, immunoprecipitates produced with either whole anti-SecA-LacZ rabbit antiserum or affinity-purified antibodies were used to analyze nondenatured lysates of Escherichia coli. The antiserum contains antibodies that recognize different proteins. Antibody purified by preadsorption to the SecA-LacZ hybrid protein precipitate
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5. Índices para a quantificação da seca.
Introdução. Tipos de seca. Índices de seca. Índice de aridez.
Santo Antônio de Goiás: Embrapa Arroz e Feijão. Publicado em: 2011
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6. Regulation of Escherichia coli secA by Cellular Protein Secretion Proficiency Requires an Intact Gene X Signal Sequence and an Active Translocon
secA is translationally regulated by the protein secretion proficiency state of the Escherichia coli cell. This regulation was explored by making signal sequence mutations in the gene upstream of secA, gene X, which promotes secA translational coupling. Gene X signal sequence mutants were constitutive for secA expression, while prlA alleles partially restore
American Society for Microbiology.
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7. Differential Dependence of Levansucrase and α-Amylase Secretion on SecA (Div) during the Exponential Phase of Growth of Bacillus subtilis
SecA, the translocation ATPase of the preprotein translocase, accounts for 0.25% of the total protein in a degU32(Hy) Bacillus subtilis strain in logarithmic phase. The SecA level remained constant irrespective of the demand for exoprotein production but dropped about 12-fold during the late stationary phase. Modulation of the level of functional SecA during
American Society for Microbiology.
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8. Binding, activation and dissociation of the dimeric SecA ATPase at the dimeric SecYEG translocase
The bacterial preprotein translocase is comprised of a membrane-embedded oligomeric SecYEG structure and a cytosolic dimeric SecA ATPase. The associations within SecYEG oligomers and SecA dimers, as well as between these two domains are dynamic and reversible. Here, it is shown that a covalently linked SecYEG dimer forms a functional translocase and a high a
Oxford University Press.
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9. Dissociation of the dimeric SecA ATPase during protein translocation across the bacterial membrane
The ATPase SecA mediates post-translational translocation of precursor proteins through the SecYEG channel of the bacterial inner membrane. We show that SecA, up to now considered to be a stable dimer, is actually in equilibrium with a small fraction of monomers. In the presence of membranes containing acidic phospholipids or in certain detergents, SecA comp
Oxford University Press.
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10. Two Nonredundant SecA Homologues Function in Mycobacteria
The proper extracytoplasmic localization of proteins is an important aspect of mycobacterial physiology and the pathogenesis of Mycobacterium tuberculosis. The protein export systems of mycobacteria have remained unexplored. The Sec-dependent protein export pathway has been well characterized in Escherichia coli and is responsible for transport across the cy
American Society for Microbiology.
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11. Comparative characterization of SecA from the alpha-subclass purple bacterium Rhodobacter capsulatus and Escherichia coli reveals differences in membrane and precursor specificity.
We have cloned the secA gene of the alpha-subclass purple bacterium Rhodobacter capsulatus, a close relative to the mitochondrial ancestor, and purified the protein after expression in Escherichia coli. R. capsulatus SecA contains 904 amino acids with 53% identity to E. coli and 54% identity to Caulobacter crescentus SecA. In contrast to the nearly equal par
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12. SecA protein autogenously represses its own translation during normal protein secretion in Escherichia coli.
The Escherichia coli secA gene, whose expression is responsive to the protein secretion status of the cell, is the second gene in an operon. We found that both the basal and induced levels of SecA biosynthesis are dependent on prior translation of the upstream gene, gene X, and identified two large gene X-secA transcripts. The 10-fold derepression of secA ex
