Abstract:
:FabG performs the NADPH-dependent reduction of β-keto acyl-acyl carrier protein substrates in the elongation cycle of fatty acid synthesis. We report the characterization of a temperature-sensitive mutation (fabGΔ8) in Escherichia colifabG that results from an in-frame 8-amino-acid residue deletion in the α6/α7 subdomain. This region forms part of one of the two dimerization interfaces of this tetrameric enzyme and is reported to undergo significant conformational changes upon cofactor binding, which define the entrance to the active-site cleft. The activity of the mutant enzyme is extremely thermolabile and is deficient in forming homodimers at nonpermissive temperatures with a corresponding decrease in fatty acid synthesis both in vivo and in vitro Surprisingly, the fabGΔ8 strain reverts to temperature resistance at a rate reminiscent of that of a point mutant with intragenic pseudorevertants located either on the 2-fold axes of symmetry or at the mouth of the active-site cleft. The fabGΔ8 mutation also confers resistance to the calmodulin inhibitor trifluoperazine and renders the enzyme extremely sensitive to Ca2+in vitro We also observed a significant alteration in the lipid A fatty acid composition of fabGΔ8 strains but only in an lpxC background, probably due to alterations in the permeability of the outer membrane. These observations provide insights into the structural dynamics of FabG and hint at yet another point of regulation between fatty acid and lipid A biosynthesis.IMPORTANCE Membrane lipid homeostasis and its plasticity in a variety of environments are essential for bacterial survival. Since lipid biosynthesis in bacteria and plants is fundamentally distinct from that in animals, it is an ideal target for the development of antibacterial therapeutics. FabG, the subject of this study, catalyzes the first cofactor-dependent reduction in this pathway and is active only as a tetramer. This study examines the interactions responsible for tetramerization through the biochemical characterization of a novel temperature-sensitive mutation caused by a short deletion in an important helix-turn-helix motif. The mutant strain has altered phospholipid and lipid A compositions and is resistant to trifluoperazine, an inhibitor of mammalian calmodulin. Understanding its structural dynamics and its influence on lipid A synthesis also allows us to explore lipid homeostasis as a mechanism for antibiotic resistance.
journal_name
J Bacterioljournal_title
Journal of bacteriologyauthors
Srinivas S,Cronan JEdoi
10.1128/JB.00074-17subject
Has Abstractpub_date
2017-04-25 00:00:00issue
10eissn
0021-9193issn
1098-5530pii
JB.00074-17journal_volume
199pub_type
杂志文章abstract::The effects of high doses of radiation (1, 5, or 20 Mrad) on the toxicity, pyrogenicity, and immunogenicity of Salmonella typhimurium cells and endotoxin were studied. Toxicity decreased progressively after exposure to 1, 5, or 20 Mrad. The lethal effect of 1-Mrad exposed cells was greater than that of heat-, acetone-...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.95.6.2165-2170.1968
更新日期:1968-06-01 00:00:00
abstract::The O antigen of the Shigella flexneri lipopolysaccharide (LPS) is an important virulence determinant and immunogen. We have isolated S. flexneri mutants which produce a semi-rough LPS by using an O-antigen-specific phage, Sf6c. Western immunoblotting was used to show that the LPS produced by the semi-rough mutants co...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/jb.176.3.733-747.1994
更新日期:1994-02-01 00:00:00
abstract::Multitrichously polar flagellated mutants were isolated from a monotrichously flagellated strain of Pseudomonas aeruginosa. The ability of the mutant cells to swarm in semisolid media at given gel strengths was increased by the multiflagellation. Observations of the mutant cells by electron microscopy revealed that th...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.143.3.1471-1479.1980
更新日期:1980-09-01 00:00:00
abstract::Pseudomonas aeruginosa is an opportunistic pathogen that causes a number of infections in humans, but is best known for its association with cystic fibrosis. It is able to use a wide range of sulfur compounds as sources of sulfur for growth. Gene expression in response to changes in sulfur supply was studied in P. aer...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.00889-07
更新日期:2007-10-01 00:00:00
abstract::The control of expression of the Bacillus subtilis spoIIA locus was analyzed by titrating gene expression against gene copy number. A plasmid integrated into the B. subtilis chromosome and carrying the spoIIA control region fused to Escherichia coli lacZ was forced to form tandem repeats by the selection of clones tha...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/jb.169.3.1260-1266.1987
更新日期:1987-03-01 00:00:00
abstract::An approach originally designed to identify functional origins of conjugative transfer (oriT or mob) in a bacterial genome (J. A. Herrera-Cervera, J. M. Sanjuán-Pinilla, J. Olivares, and J. Sanjuán, J. Bacteriol. 180:4583-4590, 1998) was modified to improve its reliability and prevent selection of undesired false mob ...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.186.17.5753-5761.2004
更新日期:2004-09-01 00:00:00
abstract::A periplasmic protein essential for the function of the oligopeptide transport system of Salmonella typhimurium was identified. This protein, encoded by the oppA gene, is one of the most abundant proteins in the periplasm and, with an apparent molecular weight of 52,000, is considerably larger than any other known per...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.155.3.1434-1438.1983
更新日期:1983-09-01 00:00:00
abstract::The P fimbrial gene clusters encoding the serologically different F7(1), F7(2), F9, and F11 fimbriae were compared functionally. The results show that these gene clusters are closely related. ...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/jb.167.1.407-410.1986
更新日期:1986-07-01 00:00:00
abstract::Mycelial mats of Ascodesmis sphaerospora were fixed and embedded for electron microscopy, and thin sections of 1-mm blocks, taken from the 1st to the 7th mm behind the hyphal tips, were cut parallel to the long axis of the hyphae. The hyphal tip region is characterized by an outer zone of electron-transparent vesicles...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.95.2.658-671.1968
更新日期:1968-02-01 00:00:00
abstract::Mutants of Bacillis subtilis that are temperature sensitive for RNA synthesis during sporulation were isolated after selection with a 32P suicide agent. Whole-genome sequencing revealed that two of the mutants carried an identical lesion in the rsbU gene, which encodes a phosphatase that indirectly activates SigB, the...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.00212-17
更新日期:2017-06-27 00:00:00
abstract::Escherichia coli K-12, polAl(-) is a mutant strain whose extracts are deficient in Kornberg deoxyribonucleic acid (DNA) polymerase activity. We have compared the mutant and parental strains on the basis of a number of responses to ultraviolet (UV) and X-irradiation. For both types of radiation, the mutant is more sens...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.107.1.61-67.1971
更新日期:1971-07-01 00:00:00
abstract::Horizontal gene transfer by conjugation plays a major role in bacterial evolution, allowing the acquisition of new traits, such as virulence and resistance to antibacterial agents. With the increased antibiotic resistance in bacterial pathogens, a better understanding of how bacteria modulate conjugation under changin...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.02279-14
更新日期:2015-03-01 00:00:00
abstract::Rhizobia form a symbiotic relationship with plants of the legume family to produce nitrogen-fixing root nodules under nitrogen-limiting conditions. We have examined the importance of glutathione (GSH) during free-living growth and symbiosis of Sinorhizobium meliloti. An S. meliloti mutant strain (SmgshA) which is unab...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.187.1.168-174.2005
更新日期:2005-01-01 00:00:00
abstract::Cyclic 2,3-diphosphoglycerate synthetase (cDPGS) catalyzes the synthesis of cyclic 2,3-diphosphoglycerate (cDPG) by formation of an intramolecular phosphoanhydride bond in 2,3-diphosphoglycerate. cDPG is known to be accumulated to high intracellular concentrations (>300 mM) as a putative thermoadapter in some hyperthe...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.180.22.5997-6004.1998
更新日期:1998-11-01 00:00:00
abstract::An ADP-ribosylating toxin named Aeromonas salmonicida exoenzyme T (AexT) in A. salmonicida subsp. salmonicida, the etiological agent of furunculosis in fish, was characterized. Gene aexT, encoding toxin AexT, was cloned and characterized by sequence analysis. AexT shows significant sequence similarity to the ExoS and ...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/jb.184.7.1851-1858.2002
更新日期:2002-04-01 00:00:00
abstract::Sinorhizobium meliloti, the nitrogen-fixing symbiont of alfalfa, has the ability to catabolize myo-, scyllo-, and D-chiro-inositol. Functional inositol catabolism (iol) genes are required for growth on these inositol isomers, and they play a role during plant-bacterium interactions. The inositol catabolism genes compr...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.05371-11
更新日期:2011-10-01 00:00:00
abstract::Fatty acid desaturation catalyzed by fatty acid desaturases requires molecular oxygen (O(2)). Saccharomyces cerevisiae cells derepress expression of OLE1 encoding Delta9 fatty acid desaturase under hypoxic conditions to allow more-efficient use of limited O(2). It has been proposed that aerobic conditions lead to repr...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.183.2.745-751.2001
更新日期:2001-01-01 00:00:00
abstract::The protein compositions of the membrane preparations from Selenomonas ruminantium grown in glucose or lactate medium were determined by sodium dodecyl sulfate- and two-dimensional (first, isoelectric focusing; second, sodium dodecyl sulfate) polyacrylamide slab gel electrophoresis. The outer membrane from both glucos...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.141.2.899-907.1980
更新日期:1980-02-01 00:00:00
abstract::The Arctic plant growth-promoting rhizobacterium Pseudomonas putida GR12-2 secretes an antifreeze protein (AFP) that promotes survival at subzero temperatures. The AFP is unusual in that it also exhibits a low level of ice nucleation activity. A DNA fragment with an open reading frame encoding 473 amino acids was clon...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.186.17.5661-5671.2004
更新日期:2004-09-01 00:00:00
abstract::The growth of Bacillus subtilis mutant betaA177 can be inhibited under special conditions in which not enough autolytic enzymes are produced for optimal growth. Electron microscopy studies show that during growth inhibition there is localized thickening of the cell wall at positions where cells bend. A model is propos...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.109.3.1247-1257.1972
更新日期:1972-03-01 00:00:00
abstract::Insertion-duplication mutagenesis was used to generate mutants of Streptococcus pneumoniae that produced truncated forms of PspA (pneumococcal surface protein A). The truncated products, representing from 20 to 80% of the complete PspA molecule, were all secreted from the cell and could be detected in unconcentrated c...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/jb.174.2.610-618.1992
更新日期:1992-01-01 00:00:00
abstract::Escherichia coli produces polysaccharide capsules that, based on their mechanisms of synthesis and assembly, have been classified into four groups. The group 4 capsule (G4C) polysaccharide is frequently identical to that of the cognate lipopolysaccharide O side chain and has, therefore, also been termed the O-antigen ...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.187.15.5259-5266.2005
更新日期:2005-08-01 00:00:00
abstract::Bacteriophage phi29 protein p6 is a viral architectural protein, which binds along the whole linear phi29 DNA in vivo and is involved in initiation of DNA replication and transcription control. Protein p1 is a membrane-associated viral protein, proposed to attach the viral genome to the cell membrane. Protein p17 is i...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.186.24.8401-8406.2004
更新日期:2004-12-01 00:00:00
abstract::Overexpression of vsr in Escherichia coli stimulates transition and frameshift mutations. The pattern of mutations suggests that mutagenesis is due to saturation or inactivation of dam-directed mismatch repair. ...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/jb.178.14.4294-4296.1996
更新日期:1996-07-01 00:00:00
abstract::Two unusual characteristics of some outer membrane proteins of Rhizobium leguminosarum are described. First, most of the major outer membrane proteins could only be visualized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis after lysozyme treatment of the isolated cell envelopes, suggesting a very strong,...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/jb.171.7.3989-3995.1989
更新日期:1989-07-01 00:00:00
abstract::Transcription of the archaeal trkA gene homolog in Methanosarcina mazei S-6 was studied at the optimal growth temperature of 37 degrees C and after heat shock at 45 degrees C. Northern (RNA) blotting results (transcript size) and data from primer extension experiments to map the transcription initiation site indicate ...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/jb.177.21.6077-6082.1995
更新日期:1995-11-01 00:00:00
abstract::Johnson, Russell C. (University of Minnesota, Minneapolis), and Palmer Rogers. Differentiation of pathogenic and saprophytic leptospires with 8-azaguanine. J. Bacteriol. 88:1618-1623. 1964.-The use of the purine analogue, 8-azaguanine, as a differential agent for the separation of pathogenic and saprophytic leptospire...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.88.6.1618-1623.1964
更新日期:1964-12-01 00:00:00
abstract::We have sequenced the rightmost 1,700 base pairs of bacteriophage PRD1. This region encompasses the right early region and completes the sequence of all PRD1 early functions. We have also mapped the 5' initiation site of right early transcripts in vivo and in vitro. This has allowed us to assign gene XII to an open re...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/jb.172.4.1889-1898.1990
更新日期:1990-04-01 00:00:00
abstract::A specialized transducing phage lambda carrying the structural gene for the OmpF protein, an outer membrane matrix protein, was isolated. The phage carries the 20.5--21-min region of the Escherichia coli K-12 chromosome and carries asnS, ompF, and aspC genes. ...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.145.2.1085-1090.1981
更新日期:1981-02-01 00:00:00
abstract::The cell wall lipopolysaccharides from 17 species belonging to the genus Xanthomonas were extracted from the cells with hot 45% phenol. After purification, the components of the polysaccharide were obtained by acid hydrolysis of the lipopolysaccharide and were quantitatively assayed. Data obtained show that all prepar...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.95.3.980-982.1968
更新日期:1968-03-01 00:00:00