Legionella pneumophila,the causative agent of Legionnaires' disease,has been recognized as a major health problem responsible for an estimated number of 15 000-30 000 cases of severe pneumonia per year in Germany ...Legionella pneumophila,the causative agent of Legionnaires' disease,has been recognized as a major health problem responsible for an estimated number of 15 000-30 000 cases of severe pneumonia per year in Germany alone.Despite of the high clinical relevance,many aspects of the intracellular life cycle of Legionella,especially details on interactions with host cells,are not well understood.Structural information on virulence proteins helps unravel basal pathogenicity mechanisms and is a prerequisite for the rational development of effective drug molecules.Here we discuss structures of three important virulence proteins of Legionella that have been determined in our laboratory.The structure of the macrophage infectivity potentiator(Mip) protein of Legionella pneumophila is the first of a novel subgroup within the family of FK506-binding protein(FKBP) peptidyl-prolyl cis/trans isomerases.On the basis of the Mip structure,promising antibacterial agents are being designed.Recently,structures of two equally exciting Legionella proteins have been reported.The ferrous iron transport protein FeoB is a transmembrane protein responsible for Fe2+ aquisition after entry of the pathogen into the host cell.The structure of the cytoplasmic domain of FeoB provides insights into the family of prokaryotic G proteins and allows a detailed comparison with structures of related FeoBs.Furthermore,the characterization of DegQ,a periplasmatic chaperone-protease involved in protein quality control represents an intriguing example of how enzymatic activity is regulated by oligomerization as well as by an intrinsic loop activation cascade,depending on subtle conformational rearrangements.展开更多
An ancient wood layer dated at about 5600 cal. a BP by AMS14C dating was discovered in the intertidal zone, East China Sea. Samples affected by ancient woods, including fresh coast bedrock, weathering bedrock, seepage...An ancient wood layer dated at about 5600 cal. a BP by AMS14C dating was discovered in the intertidal zone, East China Sea. Samples affected by ancient woods, including fresh coast bedrock, weathering bedrock, seepage water from coast, seepage water from ancient wood layer, intertidal seawater, fresh water, beach mud, ancient wood barks and ancient peat, were collected for geochemical analysis. The beach mud and the bacteriogenic iron oxides (BIOS) in coastal seepage water were analyzed by min-eralogical and high-resolution transmission electron microscopy (HRTEM)-selected area electron dif-fraction (SAED) analysis. Inorganic sulfur compositions and δ34S of the ancient peat and the beach mud were determined. The results showed that Fe, Mn, S (SO42-) were enriched in the intertidal area at different levels, very likely caused by fermentation of ancient woods. The presence of abundant iron-oxidizing bacteria (FeOB) and sulfate-reducing bacteria (SRB) in this intertidal zone was confirmed by HRTEM-SAED observation, and these bacteria were involved in Fe-S cycle to induce extracellular biomineralization. The negative δ34SV-CDT (-2.9‰) likely indicated the biogenic origin of iron-sulfide minerals in the beach mud at high sulfate reduction rate (SRR). These findings are helpful for under-standing the biogeochemical Fe-S cycle and biomineralization process at high organic matter deposition rate and high SRR in the intertidal zone, estuary, or near shoreline.展开更多
基金sponsored by Chinese Academy of Sciences Visiting Professorship for Senior International Scientists(2010T1S6)by the DFG Cluster of Excellence"Inflammation at Interfaces"(EXC 306)by the Fonds der Chemischen Industrie
文摘Legionella pneumophila,the causative agent of Legionnaires' disease,has been recognized as a major health problem responsible for an estimated number of 15 000-30 000 cases of severe pneumonia per year in Germany alone.Despite of the high clinical relevance,many aspects of the intracellular life cycle of Legionella,especially details on interactions with host cells,are not well understood.Structural information on virulence proteins helps unravel basal pathogenicity mechanisms and is a prerequisite for the rational development of effective drug molecules.Here we discuss structures of three important virulence proteins of Legionella that have been determined in our laboratory.The structure of the macrophage infectivity potentiator(Mip) protein of Legionella pneumophila is the first of a novel subgroup within the family of FK506-binding protein(FKBP) peptidyl-prolyl cis/trans isomerases.On the basis of the Mip structure,promising antibacterial agents are being designed.Recently,structures of two equally exciting Legionella proteins have been reported.The ferrous iron transport protein FeoB is a transmembrane protein responsible for Fe2+ aquisition after entry of the pathogen into the host cell.The structure of the cytoplasmic domain of FeoB provides insights into the family of prokaryotic G proteins and allows a detailed comparison with structures of related FeoBs.Furthermore,the characterization of DegQ,a periplasmatic chaperone-protease involved in protein quality control represents an intriguing example of how enzymatic activity is regulated by oligomerization as well as by an intrinsic loop activation cascade,depending on subtle conformational rearrangements.
基金Supported by the Project of the Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No. KZCX3-SW-151)
文摘An ancient wood layer dated at about 5600 cal. a BP by AMS14C dating was discovered in the intertidal zone, East China Sea. Samples affected by ancient woods, including fresh coast bedrock, weathering bedrock, seepage water from coast, seepage water from ancient wood layer, intertidal seawater, fresh water, beach mud, ancient wood barks and ancient peat, were collected for geochemical analysis. The beach mud and the bacteriogenic iron oxides (BIOS) in coastal seepage water were analyzed by min-eralogical and high-resolution transmission electron microscopy (HRTEM)-selected area electron dif-fraction (SAED) analysis. Inorganic sulfur compositions and δ34S of the ancient peat and the beach mud were determined. The results showed that Fe, Mn, S (SO42-) were enriched in the intertidal area at different levels, very likely caused by fermentation of ancient woods. The presence of abundant iron-oxidizing bacteria (FeOB) and sulfate-reducing bacteria (SRB) in this intertidal zone was confirmed by HRTEM-SAED observation, and these bacteria were involved in Fe-S cycle to induce extracellular biomineralization. The negative δ34SV-CDT (-2.9‰) likely indicated the biogenic origin of iron-sulfide minerals in the beach mud at high sulfate reduction rate (SRR). These findings are helpful for under-standing the biogeochemical Fe-S cycle and biomineralization process at high organic matter deposition rate and high SRR in the intertidal zone, estuary, or near shoreline.
