Abstract:
:Transition metals are essential for life but are toxic when in excess. Metal ion intoxication may result from the mismetallation of essential metal-dependent enzymes with a noncognate metal. To begin to identify enzymes and processes that are susceptible to mismetallation, we have selected for strains with increased resistance to Mn(II) and Co(II). In Bacillus subtilis, cells lacking the MntR metalloregulator are exquisitely sensitive to Mn(II) but can easily become resistant by acquiring mutations affecting the MntH Mn(II) importer. Using transposon mutagenesis, and starting with an mntR mntH strain, we recovered mariner insertions that inactivated the mpfA gene encoding a putative Mg(II) efflux system. Loss of MpfA leads to elevated intracellular Mg(II), increased sensitivity to high Mg(II), and reduced Mn(II) sensitivity. Consistently, we also recovered an insertion disrupting the mgtE riboswitch, which normally restricts expression of the major Mg(II) importer. These results suggest that Mn(II) intoxication results from disruption of a Mg(II)-dependent enzyme or process. Mutations that inactivate MpfA were also recovered in a selection for Co(II) resistance beginning with sensitized strains lacking the major Co(II) efflux pump, CzcD. Since both Mn(II) and Co(II) may mismetallate iron-dependent enzymes, we repeated the selections under conditions of iron depletion imposed by expression of the Listeria monocytogenes FrvA iron exporter. Under conditions of iron depletion, a wider variety of suppressor mutations were recovered, but they still point to a central role for Mg(II) in maintaining metal ion homeostasis.IMPORTANCE Cellular metal ion homeostasis is tightly regulated. When metal ion levels are imbalanced, or when one metal is at toxic levels, enzymes may bind to the wrong metal cofactor. Enzyme mismetallation can impair metabolism, lead to new and deleterious reactions, and cause cell death. Beginning with Bacillus subtilis strains genetically sensitized to metal intoxication through loss of efflux or by lowering intracellular iron, we identified mutations that suppress the deleterious effects of excess Mn(II) or Co(II). For both metals, mutations in mpfA, encoding a Mg(II) efflux pump, suppressed toxicity. These mutant strains have elevated intracellular Mg(II), suggesting that Mg(II)-dependent processes are very sensitive to disruption by transition metals.
journal_name
J Bacterioljournal_title
Journal of bacteriologyauthors
Pi H,Wendel BM,Helmann JDdoi
10.1128/JB.00711-19subject
Has Abstractpub_date
2020-03-11 00:00:00issue
7eissn
0021-9193issn
1098-5530pii
JB.00711-19journal_volume
202pub_type
杂志文章abstract::The virD locus of Agrobacterium tumefaciens Ti plasmid pTiA6 was sequenced. Computer analysis of the sequence indicated five possible open reading frames (ORFs) within this locus. Two additional ORFs were identified distal to this locus. However, only two polypeptides of apparent molecular masses 16 and 56 kilodaltons...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/jb.169.11.5035-5045.1987
更新日期:1987-11-01 00:00:00
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journal_title:Journal of bacteriology
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doi:
更新日期:1998-12-01 00:00:00
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journal_title:Journal of bacteriology
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doi:10.1128/jb.176.6.1796-1800.1994
更新日期:1994-03-01 00:00:00
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pub_type: 杂志文章
doi:10.1128/jb.174.10.3355-3363.1992
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journal_title:Journal of bacteriology
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更新日期:2012-09-01 00:00:00
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journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/jb.173.8.2665-2672.1991
更新日期:1991-04-01 00:00:00
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pub_type: 杂志文章
doi:10.1128/JB.187.4.1527-1532.2005
更新日期:2005-02-01 00:00:00
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journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/jb.177.14.3979-3984.1995
更新日期:1995-07-01 00:00:00
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journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.00006-06
更新日期:2006-06-01 00:00:00
abstract::D-[alpha-14C]]glucosyl phosphorylpolyprenol ([ 14C]Glc-P-prenol) was formed from UDP-D-[14C]glucose in each of the membrane systems obtained from Bacillus coagulans AHU 1631 and AHU 1634 and two Bacillus megaterium strains. Membranes of these B. coagulans strains, which possess beta-D-glucosyl branches on the repeatin...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/jb.171.5.2835-2841.1989
更新日期:1989-05-01 00:00:00
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journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/jb.172.9.5089-5096.1990
更新日期:1990-09-01 00:00:00
abstract::Exfoliative toxin type B is produced by bacteriophage group II strains of Staphylococcus aureus and is a causative agent of staphylococcal scalded-skin syndrome. In addition to exfoliative toxin B, most isolates also produce a bacteriocin and are immune to the action of the bacteriocin. These phenotypes, as well as re...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/jb.166.2.574-580.1986
更新日期:1986-05-01 00:00:00
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journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.155.1.186-195.1983
更新日期:1983-07-01 00:00:00
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journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/jb.172.2.802-807.1990
更新日期:1990-02-01 00:00:00
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journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.00208-18
更新日期:2018-10-10 00:00:00
abstract::Ellar, D. J. (Syracuse University, Syracuse, N.Y.), and D. G. Lundgren. Fine structure of sporulation in Bacillus cereus grown in a chemically defined medium. J. Bacteriol. 92:1748-1764. 1966.-A study was made of the fine structure of sporulating cells of Bacillus cereus grown in a chemically defined medium. The devel...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.92.6.1748-1764.1966
更新日期:1966-12-01 00:00:00
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journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/jb.166.1.38-43.1986
更新日期:1986-04-01 00:00:00
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journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.96.5.1760-1767.1968
更新日期:1968-11-01 00:00:00
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pub_type: 杂志文章
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更新日期:2002-10-01 00:00:00
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journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/jb.173.1.197-203.1991
更新日期:1991-01-01 00:00:00
abstract::In Aerobacter aerogenes, the mutational event permitting the utilization of d-arabinose as a source of carbon and energy is a regulatory mutation resulting in the constitutive synthesis of certain enzymes of the l-fucose catabolic pathway. l-Fucose isomerase catalyzes the isomerization of d-arabinose to d-ribulose. Th...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.108.1.293-299.1971
更新日期:1971-10-01 00:00:00
abstract::Transcriptional factor CarD is the only reported prokaryotic analog of eukaryotic high-mobility-group A (HMGA) proteins, in that it has contiguous acidic and AT hook DNA-binding segments and multifunctional roles in Myxococcus xanthus carotenogenesis and fruiting body formation. HMGA proteins are small, randomly struc...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/jb.185.12.3527-3537.2003
更新日期:2003-06-01 00:00:00
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journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.135.2.295-299.1978
更新日期:1978-08-01 00:00:00
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journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/jb.176.24.7730-7734.1994
更新日期:1994-12-01 00:00:00
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journal_title:Journal of bacteriology
pub_type: 杂志文章
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更新日期:2007-06-01 00:00:00
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journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/jb.178.15.4438-4444.1996
更新日期:1996-08-01 00:00:00
abstract::Amplification of the mraY gene, previously called open reading frame Y (ORF-Y, 1,080 bp), at 2 min in the chromosome map of Escherichia coli enhanced the activity of UDP-N-acetylmuramoyl-pentapeptide: undecaprenyl-phosphate phospho-N-acetylmuramoyl-pentapeptide transferase (EC 2.7.8.13). This enzyme catalyzes the form...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/jb.173.3.1021-1026.1991
更新日期:1991-02-01 00:00:00
abstract::Cobalt is essential for growth of Salmonella enterica and other organisms, yet this metal can be toxic when present in excess. Wild-type Salmonella exhibits several metabolic defects when grown in the presence of cobalt, some of which generate visible growth consequences. Work herein identifies sulfur assimilation, ir...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.00962-07
更新日期:2007-11-01 00:00:00
abstract::In response to iron limitation, the siderophore enterobactin is synthesized and secreted by Escherichia coli. Its biosynthesis is performed by a series of enzymes encoded by the Ent gene cluster. Among the genes of this cluster, ybdB has not been implicated in enterobactin production to date. We demonstrate here an in...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.00755-07
更新日期:2007-10-01 00:00:00