共查询到20条相似文献,搜索用时 15 毫秒
1.
Martinez-Canamero M Ortiz-Codorniu C Extremera AL Munoz-Dorado J Arias JM 《Antonie van Leeuwenhoek》2003,83(4):361-368
A soil bacterium able to undergo multicellular development and a coordinated gliding in swarms, requires an accurate regulatory
network of phosphorelay proteins. Inorganic phosphate is a limiting nutrient in soil and its importance in regulation is critical.
As a step towards studying phosphate regulation and its influence in the developmental process in this bacterium, we screened
a Myxococcus xanthus library for clones with phosphatase activity, and found four different ones. The deduced sequence of one of the cloned inserts
is similar to that of the classic transmembrane histidine protein kinase of the sensor family of the two-component signal
transduction systems with a high sequence similarity to the sensor kinase in the Pho regulon of Bacillus subtilis PhoR. This gene has been named phoR1 and its deduced amino acid sequence consists of 455 residues with a predicted molecular mass of 48.5 kDa. The M. xanthus PhoR1 deduced sequence contains all the characteristic histidine protein kinase motifs in the same order and with the same
spacing. A hydropathy profile indicates two membrane-spanning segments located at the extreme N-terminus, according to the
putative sensor role of this domain. A gene-disrupted mutant is unable to produce normal mature fruiting bodies and produces
fewer spores.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
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Dongmei Li David Williams Douglas Lowman Mario A. Monteiro Xuan Tan Michael Kruppa William Fonzi Elvira Roman Jesus Pla Richard Calderone 《Fungal genetics and biology : FG & B》2009,46(10):731-741
Several published functions associated with the CHK1 histidine kinase of Candida albicans resemble those of the MAPK Cek1p and its cognate receptor Sho1p (SSU81). To explore this further, we have compared mutants lacking the proteins mentioned above and have constructed a double sho1/chk1Δ null mutant to determine relationships among these proteins. We observed that the sensitivity to Congo red (CR), calcofluor white (CW), as well as clumping of cells, was slightly increased in the double mutant compared to the single chk1Δ or sho1Δ mutants. However, Cek1p phosphorylation via Sho1p, which occurs during log phase growth in the presence or absence of CR in Wt cells, does not require Chk1p. These data suggest that Chk1p and Sho1p are components of parallel but independent signal pathways. In addition, bulk mannan of strains was analyzed by GLC/MS and GPC MALLS and NMR. Compared to Wt and a CHK1 gene-reconstituted strain (CHK23) that contained high, intermediate and low Mw mannan species, we found that the mannan of strains CHK21 (chk1Δ null), the cek1Δ null, and the double mutant consisted only of low Mw mannan. The sho1Δ null mutant only demonstrated a reduced intermediate type of mannan. Alcian blue binding was lower in cek1Δ, chk1Δ, and the double sho1/chk1Δ null mutant lacking high and intermediate Mw mannan than in the sho1Δ null which had a partial loss of intermediate Mw mannan only. We conclude that the Chk1p HK is part of a functionally similar but parallel pathway to the Sho1p-Cek1p pathway that confers resistance to the cell wall inhibitors CR and CW. However, a functional relationship in mannan biosynthesis of Chk1p and Cek1p exists that only partially requires Sho1p. 相似文献
3.
Membranes isolated from pea buds contain protein-kinase activity which is greatly activated by low concentrations of calcium ions. This paper describes a simple purification of this enzyme with a novel means of detecting enzyme activity by Western blotting. The purified enzyme appears to autophosphorylate primarily on serine residues, is activated by bovine calmodulin and additional evidence from phase partitioning indicate most of this enzyme to be located in the plasma membrane.Abbreviations PAGE
polyacrylamide-gel electrophoresis
- SDS
sodium dodecyl sulphate 相似文献
4.
Kefala G Kwiatkowski W Esquivies L Maslennikov I Choe S 《Journal of structural and functional genomics》2007,8(4):167-172
Integral membrane proteins have become the focus of interest of many laboratories and structural genomics consortia, but their
study is hampered by bottlenecks in production, solubilization, purification and crystallization. In our laboratory we have
addressed the problem of high-level protein expression in the membrane of Escherichia coli by use of Mistic, a novel Bacillus subtilis protein, as a fusion partner. In this study we examine the effect of Mistic on protein expression and membrane integration
levels of members of the E. coli histidine kinase receptor family. We find that Mistic fusion invariably increases the overall yield by targeting the cargo
proteins more efficiently to the membrane and may even replace the signal sequence. Mistic fusion methods will likely be instrumental
for high-level expression of other integral membrane proteins. 相似文献
5.
Lozo J Jovcic B Kojic M Dalgalarrondo M Chobert JM Haertlé T Topisirovic L 《Current microbiology》2007,55(3):266-271
Screening the collection of natural isolates from semi-hard homemade cheese resulted in isolation and characterization of
strain Lactobacillus paracasei subsp. paracasei BGSJ2-8. The strain BGSJ2-8 harbors several important phenotypes, such as bacteriocin production, aggregation phenomenon,
and production of proteinase. Bacteriocin SJ was purified by three-step chromatography. Mass spectrometry established molecular
mass of the active peptide at 5372 Da. The auto-aggregation phenotype of wild-type (WT) strain was mediated by secreted aggregation-promoting
factor (protein of molecular mass > 200 kDa), probably acting in cooperation with other cell surface protein(s). Comparative
study of WT and its spontaneous nonaggregating derivative revealed that aggregation factor was responsible for the observed
differences in the bacteriocin and proteinase activities. Bacteriocin SJ activity and resistance to different stresses were
higher in the presence of aggregating factor. In contrast, proteinase activity was stronger in the nonaggregating derivative. 相似文献
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Sahar F. Deraz Martin Hedström Eva Nordberg Karlsson Sara Linse Ashraf A. Khalil Bo Mattiasson 《World journal of microbiology & biotechnology》2007,23(7):911-921
Lactobacillus acidophilus DSM 20079 is the producer of a novel bacteriocin termed acidocin D20079. In this paper, a partial sequence of this peptide
is determined, together with data on its secondary structure. A modification of the MRS-growth medium (replacing the detergent
Tween 80 with oleic acid), was shown to improve the production level of the peptide by one order of magnitude, as well as
to stabilize the activity level. Addition of a detergent (Tween 20, less interfering in mass spectrometric analysis), was
however necessary for solubilization of the purified acidocin D20079. Digestion of the peptide followed by de-novo sequencing
of generated fragments, allowed determination of a partial sequence consisting of 39 of the totally estimated 65 residues.
Acidocin D20079 has a high content of glycine residues, hydrophobic residues, and acidic residues. No modified amino acids
were found. Edman degradation, and C-terminal sequencing failed, suggesting that the peptide may be cyclic, and a novel member
of class IIc bacteriocins. Circular dichroism spectroscopy and secondary structure prediction showed random coil conformation
in aqueous solution, but secondary structure was induced in the presence of sodium-dodecyl sulfate. The data could be fitted
assuming 2–13% of the residues to be in α-helix and 23–27% of the residues to be in β-strand conformation. This indicates
that a membrane/membrane-mimicking hydrocarbon–water interface induces an active conformation. 相似文献
8.
Mitogen-activated protein kinase OsMPK6 negatively regulates rice disease resistance to bacterial pathogens 总被引:1,自引:0,他引:1
Mitogen-activated protein kinase (MAPK) cascades play important roles in diverse developmental and physiological processes
of plants, including pathogen-induced defense responses. Although at least 17 rice MAPKs have been identified and more than
half of these MAPK genes have been shown to be pathogen or elicitor responsive, the exact role of most of the MAPKs in host-pathogen
interaction is unknown. Here we report that OsMPK6 is an important regulator in rice disease resistance. Suppressing OsMPK6 or knocking out of OsMPK6 enhanced rice resistance to different races of Xanthomonas oryzae pv. oryzae, causing bacterial blight, one of the most devastating diseases of rice worldwide. The resistant plants showed increased
expression of a subset of defense-responsive genes functioning in the NH1 (an Arabidopsis NPR1 orthologue)-involved defense signal transduction pathway. These results suggest that OsMPK6 functions as a repressor
to regulate rice defense responses upon bacterial invasion.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
9.
Isolation of a cDNA encoding a homologue of actin from Porphyra yezoensis (Rhodophyta) 总被引:1,自引:0,他引:1
Yukihiro Kitade Satoru Fukuda Maiko Nakajima Toshiki Watanabe Naotsune Saga 《Journal of applied phycology》2002,14(2):135-141
We report the nucleotide sequence of a cDNA encoding an actin from amarine red alga, Porphyra yezoensis Ueda. A cDNA clone wasisolated from a leafy gametophyte cDNA library and analyzed for the sequence.The clone contained an open reading frame for a protein of 373 amino acidswhichexhibits sequence similarity to known actins. The GC content of the thirdposition (83.9%) was much higher than that at the first (56.3%) and second(42.4%) positions. The actin forms a gene family in the P.yezoensis genome. Comparison of the deduced amino acid sequenceshowed higher similarity to the Florideophycidae Chondruscrispus (85%) than to the ProtoflorideophycidaeCyanidioschyzon merolae (70%). The mRNA was detected inboth the leafy gametophytes and filamentous sporophytes. The nucleotidesequence data reported in this paper will appear in theDDBJ/EMBL/GenBank databases under accession number AB039831. 相似文献
10.
Brown R Marchesi JR Morby AP 《Biochemical and biophysical research communications》2011,411(1):132-136
Bioinformatic analysis of lp_2714 from Lactobacillus plantarum WCFS1 demonstrates that it encodes an EAL-domain protein associated with a membrane targeting signal-sequence. Comparison of the predicted primary amino-acid sequence of Lp_2714 shows that it lacks critical catalytic residues and heterologous expression has determined that it does not encode a functional phosphodiesterase. We designate Lp_2714 as a class-3 EAL domain protein probably involved in regulating polysaccharide synthesis on the cell surface the cell. 相似文献
11.
G protein Gα subunits contribute to the specificity of different signal transduction pathways in Dictyostelium discoideum but Gα subunit-effector interactions have not been previously identified. The requirement of the Dictyostelium Gα4 subunit for MAP kinase (MAPK) activation and the identification of a putative MAPK docking site (D-motif) in this subunit suggested a possible interaction between the Gα4 subunit and MAPKs. In vivo association of the Gα4 subunit and ERK2 was demonstrated by pull-down and co-immunoprecipitation assays. Alteration of the D-motif reduced Gα4 subunit-ERK2 interactions but only slightly altered MAPK activation in response to folate. Expression of the Gα4 subunit with the altered D-motif in gα4−cells allowed for slug formation but not the morphogenesis associated with culmination. Expression of this mutant Gα4 subunit was sufficient to rescue chemotactic movement to folate. Alteration of the D-motif also reduced the aggregation defect associated with constitutively active Gα4 subunits. These results suggest Gα4 subunit-MAPK interactions are necessary for developmental morphogenesis but not for chemotaxis to folate. 相似文献
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Mitogen-activated protein kinases are key-regulatory elements in the differentiation, proliferation, apoptosis and stress response of eukaryotic cells. Our recent identification of a mitogen-activated protein kinase homologue in Leishmania mexicana which is essential for the proliferation of the amastigote stage of the parasite living in the parasitophorous vacuole of the infected macrophage prompted us to screen the genome of L. mexicana for additional mitogen-activated protein kinase homologues using degenerate oligonucleotide primers in a polymerase chain reaction amplification approach. We cloned and sequenced the genes for eight new mitogen-activated protein kinase homologues which were subsequently shown to be present in one copy per haploid genome. The mRNA levels of the kinases varied significantly in pro- and amastigote life stages of the parasite. We used the structural information of the p38 stress-activated protein kinase, which belongs to the family of mitogen-activated protein kinases, for the alignment of the deduced proteins and the verification of the predicted secondary structure elements. All new mitogen-activated protein kinases reveal the typical 12 subdomain primary structure, the conserved residues characterising serine/threonine protein kinases and the characteristic TXY motif in the phosphorylation lip. Typical features of some of the molecules are amino acid insertions between the subdomains and long carboxy-terminal amino acid extensions carrying putative src-homology 3-binding motifs. 相似文献
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Plants and protozoa contain a unique family of calcium-dependent protein kinases (CDPKs) which are defined by the presence of a carboxyl-terminal calmodulin-like regulatory domain. We present biochemical evidence indicating that at least one member of this kinase family can be stimulated by 14-3-3 proteins. Isoform CPK-1 from the model plant Arabidopsis thaliana was expressed as a fusion protein in E. coli and purified. The calcium-dependent activity of this recombinant CPK-1 was shown to be stimulated almost twofold by three different 14-3-3 isoforms with 50% activation around 200 nM. 14-3-3 proteins bound to the purified CPK-1, as shown by binding assays in which either the 14-3-3 or CPK-1 were immobilized on a matrix. Both the 14-3-3 binding and activation of CPK-1 were specifically disrupted by a known 14-3-3 binding peptide LSQRQRSTpSTPNVHMV (IC50=30 μM). These results raise the question of whether 14-3-3 can modulate the activity of CDPK signal transduction pathways in plants. 相似文献
17.
S.T. Ogunbanwo A.I. Sanni A.A. Onilude 《World journal of microbiology & biotechnology》2004,20(1):57-63
Quantitative determination of antimicrobial compounds produced by the Lactobacillus strains under test was carried out. L. plantarum F1 produced the highest quantity of lactic acid (16.4 g/l) while the lowest amount (0.3 g/l) was produced by L. jensenii F9. All the test organisms produced hydrogen peroxide, with L. brevis OG1 having the highest yield of 0.037 g/l. Diacetyl was also produced by all the organisms, with L. plantarum F1 and L. brevis OG1 having the highest yield of 1.7 g/l, while the lowest producer was L. jensenii F9 (0.86 g/l). Determination of bacteriocin activity was carried out. L. plantarum F1 exhibited 6400 AU/ml bacteriocin activity, while L. brevis OG1 had the lowest activity of 3200 AU/ml using E. coli NCTC10418 as indicator organism. However, L. fermentum F5 and L. jensenii F9 did not produce any detectable bacteriocin. The pH value in the culture supernatant of L. plantarum F1 reached 3.1 within 48 h of incubation, while that of L. jensenii F9 was 5.2. Fufu was prepared using both bacteriocin-producing (BP) L. plantarum F1 and L. brevis OG1, and non-bacteriocin producing L. fermentum F5 and L. jensenii F9. No viable cells of Salmonella typhimurium ATCC13311 and Shigella flexneri AP23498 were detected after 12 h in the cassava products fermented with mixed starter culture of L. plantarum F1 and L. brevis OG1. The rate of survival of enteropathogens in cassava fermented with mixed starter cultures of L. plantarum F1 and L. brevis OG1 was much lower when compared to cassava fermented with mixed starter culture of L. fermentum F5 and L. jensenii F9. At 12 h, the viable count of E. coli NCTC10418 in cassava fermented with mixed starter cultures of L. plantarum F1 and L. brevis OG1 was 1.1 log10 c.f.u./g whereas in cassava fermented with mixed starter cultures of L. fermentum F5 and L. jensenii F9, 8.5 log10 c.f.u./g was obtained The study revealed that fufu produced with BP mixed starter cultures had a better shelf life and kept for 13 days before spoilage occurred, relative to 5 days observed for fufu produced using non-bacteriocin-producing starter cultures, and 6 days for the traditional fermented fufu. 相似文献
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To explore the mutagenic properties of the nucleotide analogue bromodeoxyuridine triphosphate (BrdUTP), the wild type α-amylase
(xamy) gene from Xanthomonas campestris pv. campestris 8004 was used as a mutational target. It was mutated using PCR techniques to partially replace deoxythymidine triphosphate
(dTTP) with BrdUTP. A total of 18 mutants were selected for DNA sequencing from the mutagenesis libraries by their ability
to hydrolyze the starch. The results showed that 70% of the total mutations were single base-pair substitutions; BrdUTP also
induced deletion and insertion mutation types. Among single base-pair substitutions, the predominant mutation type is transition
(84%), but three kinds of transversions (16%) were also detected. It thus mainly induces A:T → G:C and T:A → C:G transitions.
This result indicated that when bromouracil is present as a deoxyribonucleoside triphosphate substrate it mainly paired with
dAMP, and when it is present as a template base it could pair with free dGTP. Three mutational hot spots induced by BrdUTP
were revealed in this work. 相似文献