Biochemical data and genomic analysis indicate the involvement of a putative ABC transporter for glucose transport in Pseudomonas putida CSV86. The periplasmic solute binding proteins are known to confer substrate spe...Biochemical data and genomic analysis indicate the involvement of a putative ABC transporter for glucose transport in Pseudomonas putida CSV86. The periplasmic solute binding proteins are known to confer substrate specificity to the ABC transporters by binding specifically to the substrate and transferring them to their cognate inner membrane transport assembly. Periplasmic glucose binding protein from Pseudomonas putida CSV86 (ppGBP) was found to be glucose specific. The gene encoding ppGBP was cloned. Recombinant ppGBP was overexpressed and purified to homogeneity. The purified recombinant protein showed glucose binding activity of 752 pmol/mg of protein and was crystallized as a complex with glucose. The crystal diffracted to 1.7 Å resolution using home X-ray source. Preliminary analysis of diffraction data showed that the crystals belonged to space group P21212 with unit-cell parameters a = 102.56, b = 119.2, c = 66.65 Å and α = β = γ = 90°. Matthews coefficient calculation showed the presence of two molecules in the asymmetric unit with solvent content of 45.7%.展开更多
Reverse-transcription qualitative PCR(RT-qPCR)was used to analyze the changes in transcription levels of the sulfur metabolism-related periplasmic protein genes of Acidithiobacillus ferrooxidans ATCC 23270 grown on su...Reverse-transcription qualitative PCR(RT-qPCR)was used to analyze the changes in transcription levels of the sulfur metabolism-related periplasmic protein genes of Acidithiobacillus ferrooxidans ATCC 23270 grown on sulfur or ferrous.Seven periplasmic proteins with apparently higher abundance grown on elemental sulfur than on ferrous sulfate were identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry(MALDI-TOF-MS).Expression analysis of the corresponding genes by RT-qPCR shows that the constitutive expression of all those genes are more up-regulated grown on sulfur than those grown on ferrous(>10 folder).Study on the corresponding genes of the identified periplasmic proteins by RT-qPCR confirmed the results of two-dimensioned gel electrophoresis,indicating they may be related with sulfur metabolism in A.ferrooxidans.展开更多
Proteins secreted by Helicobacter pylori (H. pylori), an important human pathogen responsible for severe gastric diseases, are reviewed from the point of view of their biochemical characterization, both functional and...Proteins secreted by Helicobacter pylori (H. pylori), an important human pathogen responsible for severe gastric diseases, are reviewed from the point of view of their biochemical characterization, both functional and structural. Despite the vast amount of experimental data available on the proteins secreted by this bacterium, the precise size of the secretome remains unknown. In this review, we consider as secreted both proteins that contain a secretion signal for the periplasm and proteins that have been detected in the external medium in in vitro experiments. In this way, H. pylori’s secretome appears to be composed of slightly more than 160 proteins, but this number must be considered very cautiously, not only because the definition of secretome itself is ambiguous but also because the included proteins were observed as secreted in in vitro experiments that were not representative of the environmental situation in vivo. The proteins that appear to be secreted can be grouped into different classes: enzymes (48 proteins), outer membrane proteins (43), components of flagella (11), members of the cytotoxic-associated genes pathogenicity island or other toxins (8 and 5, respectively), binding and transport proteins (9), and others (11). A final group, which includes 28 members, is represented by hypothetical uncharacterized proteins. Despite the large amount of data accumulated on the H. pylori secretome, a considerable amount of work remains to reach a full comprehension of the system at the molecular level.展开更多
The nickel-resistant bacterium, Cupriavidus pauculus KPS 201 was isolated from the rhizosphere of Rinorea bengalensis (Wall.) O. K. endemic to metal-percolated ultramafic ecosystem of Andaman, India. This study invest...The nickel-resistant bacterium, Cupriavidus pauculus KPS 201 was isolated from the rhizosphere of Rinorea bengalensis (Wall.) O. K. endemic to metal-percolated ultramafic ecosystem of Andaman, India. This study investigates nature of Ni resistance, growth associated uptake and localization of Ni in cellular compartments of KPS 201. Growth kinetics of C. pauculus KPS 201 exhibited a typical inducible Ni resistance in Ni-supplemented (1.0-10.0 mM) Tris-minimal medium. The Ni-induced cells showed a high degree of Ni resistance and accumulated a maximum of 29.3 μM Ni/g protein after 48 h of growth in 5 mM Ni. The accumulated Ni was preferentially retained (90.6%) in the periplasm and was associated with the expression of two periplasmic proteins (74 and 66 kDa) under Ni-induced condition. Inducible nickel resistance in C. pauculus KPS 201 may possibly be due to extracytoplasmic binding and accumulation coupled with expression of specific periplasmic proteins. These findings will provide an insight in understanding metal-microbe interaction in geogenous environments and their exploitation in bioremediation of heavy metal pollutants.展开更多
1 Introduction Outer-membrane vesicles (OMVs) are nanoscale,bilayered particles shed by Gram-negative bacteria [1].Enriched in lipopolysaccharides (LPS),outer-membrane proteins,and periplasmic cargos (Figure 1),OMVs a...1 Introduction Outer-membrane vesicles (OMVs) are nanoscale,bilayered particles shed by Gram-negative bacteria [1].Enriched in lipopolysaccharides (LPS),outer-membrane proteins,and periplasmic cargos (Figure 1),OMVs are central to bacterial communication and host interaction,and they naturally traffic proteins,nucleic acids,and small molecules across biological barriers [2].These same traits,intrinsic immunogenicity,colloidal stability in complex fluids,and efficient cell entry,have positioned OMVs as attractive chassis for vaccines and drug delivery [3–5].Yet native vesicles are constrained by non-specific biodistribution,batch heterogeneity,reactogenic LPS,and limited control over cargo loading and release [6,7].These challenges necessitate the development of strategies to enhance their functionality and broaden their applications.展开更多
文摘Biochemical data and genomic analysis indicate the involvement of a putative ABC transporter for glucose transport in Pseudomonas putida CSV86. The periplasmic solute binding proteins are known to confer substrate specificity to the ABC transporters by binding specifically to the substrate and transferring them to their cognate inner membrane transport assembly. Periplasmic glucose binding protein from Pseudomonas putida CSV86 (ppGBP) was found to be glucose specific. The gene encoding ppGBP was cloned. Recombinant ppGBP was overexpressed and purified to homogeneity. The purified recombinant protein showed glucose binding activity of 752 pmol/mg of protein and was crystallized as a complex with glucose. The crystal diffracted to 1.7 Å resolution using home X-ray source. Preliminary analysis of diffraction data showed that the crystals belonged to space group P21212 with unit-cell parameters a = 102.56, b = 119.2, c = 66.65 Å and α = β = γ = 90°. Matthews coefficient calculation showed the presence of two molecules in the asymmetric unit with solvent content of 45.7%.
基金Projects(50674101,50974140)supported by the National Natural Science Foundation of ChinaProject(2010CB630902)supported by the National Basic Research Program of China
文摘Reverse-transcription qualitative PCR(RT-qPCR)was used to analyze the changes in transcription levels of the sulfur metabolism-related periplasmic protein genes of Acidithiobacillus ferrooxidans ATCC 23270 grown on sulfur or ferrous.Seven periplasmic proteins with apparently higher abundance grown on elemental sulfur than on ferrous sulfate were identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry(MALDI-TOF-MS).Expression analysis of the corresponding genes by RT-qPCR shows that the constitutive expression of all those genes are more up-regulated grown on sulfur than those grown on ferrous(>10 folder).Study on the corresponding genes of the identified periplasmic proteins by RT-qPCR confirmed the results of two-dimensioned gel electrophoresis,indicating they may be related with sulfur metabolism in A.ferrooxidans.
基金Supported by the University of Padua grant "Progetto di Ateneo 2011" and by PRIN 2010-2011 "Unraveling structural and functional determinants behind Helicobacter pylori pathogen-esis and persistence"
文摘Proteins secreted by Helicobacter pylori (H. pylori), an important human pathogen responsible for severe gastric diseases, are reviewed from the point of view of their biochemical characterization, both functional and structural. Despite the vast amount of experimental data available on the proteins secreted by this bacterium, the precise size of the secretome remains unknown. In this review, we consider as secreted both proteins that contain a secretion signal for the periplasm and proteins that have been detected in the external medium in in vitro experiments. In this way, H. pylori’s secretome appears to be composed of slightly more than 160 proteins, but this number must be considered very cautiously, not only because the definition of secretome itself is ambiguous but also because the included proteins were observed as secreted in in vitro experiments that were not representative of the environmental situation in vivo. The proteins that appear to be secreted can be grouped into different classes: enzymes (48 proteins), outer membrane proteins (43), components of flagella (11), members of the cytotoxic-associated genes pathogenicity island or other toxins (8 and 5, respectively), binding and transport proteins (9), and others (11). A final group, which includes 28 members, is represented by hypothetical uncharacterized proteins. Despite the large amount of data accumulated on the H. pylori secretome, a considerable amount of work remains to reach a full comprehension of the system at the molecular level.
文摘The nickel-resistant bacterium, Cupriavidus pauculus KPS 201 was isolated from the rhizosphere of Rinorea bengalensis (Wall.) O. K. endemic to metal-percolated ultramafic ecosystem of Andaman, India. This study investigates nature of Ni resistance, growth associated uptake and localization of Ni in cellular compartments of KPS 201. Growth kinetics of C. pauculus KPS 201 exhibited a typical inducible Ni resistance in Ni-supplemented (1.0-10.0 mM) Tris-minimal medium. The Ni-induced cells showed a high degree of Ni resistance and accumulated a maximum of 29.3 μM Ni/g protein after 48 h of growth in 5 mM Ni. The accumulated Ni was preferentially retained (90.6%) in the periplasm and was associated with the expression of two periplasmic proteins (74 and 66 kDa) under Ni-induced condition. Inducible nickel resistance in C. pauculus KPS 201 may possibly be due to extracytoplasmic binding and accumulation coupled with expression of specific periplasmic proteins. These findings will provide an insight in understanding metal-microbe interaction in geogenous environments and their exploitation in bioremediation of heavy metal pollutants.
基金supported by the National Key Research and Development Program of China (2021YFA1201100,2021YFA1201103,X.Zhao)the National Natural Science Foundation of China (32471450,82402462,K.Cheng)+1 种基金the Beijing Municipal Science&Technology Commission (Z231100007223011,X.Zhao)the Beijing Natural Science Foundation (7244523,K.Cheng)。
文摘1 Introduction Outer-membrane vesicles (OMVs) are nanoscale,bilayered particles shed by Gram-negative bacteria [1].Enriched in lipopolysaccharides (LPS),outer-membrane proteins,and periplasmic cargos (Figure 1),OMVs are central to bacterial communication and host interaction,and they naturally traffic proteins,nucleic acids,and small molecules across biological barriers [2].These same traits,intrinsic immunogenicity,colloidal stability in complex fluids,and efficient cell entry,have positioned OMVs as attractive chassis for vaccines and drug delivery [3–5].Yet native vesicles are constrained by non-specific biodistribution,batch heterogeneity,reactogenic LPS,and limited control over cargo loading and release [6,7].These challenges necessitate the development of strategies to enhance their functionality and broaden their applications.
