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Science China Chemistry 2020年第8期63卷 1142-1152页

作者： Chenhui He Sichen Pan Geng Li Xin Sheng Zhao School of Life Sciences Peking UniversityBeijing 100871China Biomedical Pioneering Innovation Center(BIOPIC) Peking UniversityBeijing 100871China Beijing National Laboratory for Molecular Sciences State Key Laboratory for Structural Chemistry of Unstable and Stable Speciesand Department of Chemical BiologyCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China

SurA is the major chaperone of outer membrane proteins(OMPs)in the *** molecular mechanism when SurA performs its chaperoning function is still ***,a purification-after-crosslinking(PAC)procedure was combined with single-molecule fluorescence resonance energy transfer(smFRET)to probe the conformations of SurA and OmpC in their *** found that SurA in the free state rearranges itself based on the crystal structure,except that the P2 domain moves towards the core domain with two major positions,forming a clamp-like conformation to accommodate *** obvious rearrangement of the P2 domain of SurA helps SurA to hold *** attaches to SurA randomly and has the propensity to be near the middle part of the *** noncollapsed and disordered conformations of OMPs provided by the OMPs?SurA complex are important to the subsequent delivery and folding process.

关键词： outer membrane proteins SurA smFRET crosslinking

Antimicrobial Susceptibility and Characterization of outer membrane proteins of Aeromonas hydrophila Isolated in China

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Journal of Integrative Agriculture 2014年第4期13卷 911-917页

作者： GUO Peng WANG Na LIU Yong-jie LU Cheng-ping College of Veterinary Medicine Nanjing Agricultural University Institute of Animal Quarantine Chinese Academy of Inspection and Quarantine

Aeromonas hydrophila isolates from clinical cases （n=43） were tested against 8 antimicrobial agents and typed by outer membrane protein （OMP） pattern by using sodium dodecyl sulfate gel electrophoresis. All isolates were resistant to ampicillin （MICs, ≥16 μg mL-1） and sulfamonomethoxine （MICs≥64 μg mLl）, but susceptible to norfloxacin （MICs,≤0.5 μg mL-1）. There was a high incidence of resistance to erythromycin （90.70%） and tylosin （93.02%）, while a low incidences of resistance to ciprofloxacin （2.33%）, enrofloxacin （2.33%） and florfenicol （4.65%）. Six different outer membrane protein patterns were found among 34 isolates by analyzing proteins in the range of 22 to 50 kDa, other than 9 isolates with their respective profiles. The strains with the similar OMP profiles had similar resistances. Compared with the other strains from the same OMP patterns, NB-1, *** and MR-1 had lacked the proteins in the range of 30 to 45 kDa and their resistance to florfenicol substantially increased. It is speculated that the outer membrane protein changes might correlate with decreased susceptibility to florfenicol in the three strains. Some strains which showed completely identical OMP types had a little difference in their resistance to fluoroquinolones, indicating that there might be other factors that were involved in the antimicrobial resistance of A. hydrophila.

关键词： Aeromonas hydrophila antimicrobial resistance outer membrane proteins

Immunoproteomic Analysis of Bordetella bronchiseptica outer membrane proteins and Identification of New Immunogenic proteins

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Journal of Integrative Agriculture 2014年第9期13卷 2010-2018页

作者： LIU Yan QIN Feng-yan BAO Guo-lian CHEN Hui XIAO Chen-wen WEI Qiang JI Quan-an Animal Husbandry and Veterinary Institute Zhejiang Academy of Agricultural Sciences

Bordetella bronchiseptica is a Gram-negative pathogen that causes acute and chronic respiratory infection in a variety of animals. To identify useful antigen candidates for diagnosis and subunit vaccine of B. bronchiseptica, immunoproteomic analysis was adopted to analyse outer membrane proteins of it. The outer membrane proteins extracted from B. bronchiseptica were separated by two-dimensional gel electrophoresis and analyzed by Western blotting for their reactivity with the convalescent serum against two strains. Immunogenic proteins were identified by matrix-assisted laser desorption/ionization time of flight-mass spectrometry（MALDI-TOF-MS）, a total of 14 proteins are common immunoreactive proteins, of which 1 was known antigen and 13 were novel immunogenic proteins for B. bronchiseptica. Putative lipoprotein gene was cloned and recombinantly expressed. The recombinant protein induced high titer antibody, but showed low protective indices against challenges with HB（B. bronchiseptica strain isolated from a infected rabbit）. The mortality of mice was 80% compared to 100% of positive controls. The identification of these novel antigenic proteins is an important resource for further development of a new diagnostic test and vaccine for B. bronchiseptica.

关键词： Bordetella bronchiseptica outer membrane proteins immunoproteomic analysis

Mechanism on protection of *** outer membrane proteins by periplasmic chaperones SurA and Skp

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Mechanism on protection of *** outer membrane proteins by pe...

第十届全国化学生物学学术会议

作者： Geng Li Xin Sheng Zhao Beijing National Laboratory for Molecular Sciences State Key Laboratory for Structural Chemistry of Unstable and Stable SpeciesDepartment of Chemical BiologyCollege of Chemistry and Molecular Engineeringand Biodynamic Optical Imaging Center （BIOPIC）Peking University

SurA and Skp are both periplasmic chaperones in the biogenesis of E. coli β–barrel outer membrane proteins（OMPs）. It is commonly assumed that SurA plays a major role, whereas Skp is a minor factor. However, there is no molecular evidence whether their roles are redundant or not. By using different dilution methods, we obtained monodispersed and aggregated OMPs and studied their interactions with Skp and SurA by single–molecule fluorescence resonance energy transfer（smFRET） and fluorescence correlation spectroscopy（FCS）. We found that Skp has the ability to dissolve the aggregated OMPs, while SurA can hardly convert the aggregated OMPs into a monodispersed form, and OMPs protected by the two chaperones possess different conformations and stoichiometries. Our study demonstrates the functional distinctions between Skp and SurA. Especially, Skp is not redundant and will be more significant under stressed conditions. On the other hand, by using FRET technique, we studied the molecular interaction between SurA and outer membrane protein C（OmpC） from conformations to kinetics. Our results show that after binding to OmpC, SurA basically maintains its structure but somewhat expanded, in which the distance between the N and P1 domains is most stretched, and OmpC behaves like an extended random coil in the SurA-OmpC complex. Based on our conformational and kinetic information and previous works, we propose that OMPs anchors on the crevice in SurA’s core module first, then is wrapped around SurA, and finally one of its terminals settles down on the P2 *** manner of interaction may be essential for SurA to convey OMPs to BAM system for the folding and assembling.

关键词： outer membrane proteins Chaperone smFRET FCS

Helicobacter pylori virulence genes

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World Journal of Gastroenterology 2019年第33期25卷 4870-4884页

作者： Anja Sterbenc Erika Jarc Mario Poljak Matjaz Homan Institute of Microbiology and Immunology Faculty of MedicineUniversity of LjubljanaLjubljana 1000Slovenia Department of Gastroenterology Hepatology and NutritionUniversity Children’s HospitalFaculty of MedicineUniversity of LjubljanaLjubljana 1000Slovenia

Helicobacter pylori(***)is one of the most important human pathogens,infecting approximately half of the global *** its high prevalence,only a subset of *** infected individuals develop serious gastroduodenal *** pathogenesis of *** infection and disease outcome is thus thought to be mediated by an intricate interplay between host,environmental and bacterial virulence *** has adapted to the harsh milieu of the human stomach through possession of various virulence genes that enable survival of the bacteria in the acidic environment,movement towards the gastric epithelium,and attachment to gastric epithelial *** virulence factors enable successful colonization of the gastric mucosa and sustain persistent *** infection,causing chronic inflammation and tissue damage,which may eventually lead to the development of peptic ulcers and gastric *** studies have focused on the prevalence and role of putative *** virulence genes in disease *** several virulence factors with various functions have been identified,disease associations appear to be less evident,especially among different study *** review presents key findings on the most important *** virulence genes,including several bacterial adhesins and toxins,in children and adults,and focuses on their prevalence,clinical significance and potential relationships.

关键词： Helicobacter pylori Virulence genes Disease association Children Adults outer membrane proteins Bacterial toxins

Comparison of Lipopolysaccharide and Protein Immunogens from Pathogenic Yersinia enterocolitica Bio-serotype 1B/O:8 and 2/O:9 using SDS-PAGE

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Biomedical and Environmental Sciences 2012年第3期25卷 282-290页

作者： GU Wen Peng WANG Xin QIU Hai Yan LUO Xia XIAO Yu Chun TANG Liu Ying KAN Biao XU Jian Guo JING Huai Qi National Institute for Communicable Disease Control and Prevention Chinese Center for Disease Control and PreventionState Key Laboratory Jbr Infectious Disease Prevention and Control Beijing 102206China National Institute for Viral Disease Control and Prevention Chinese Center for Disease Control and PreventionBeijing 102206China

Objective Yersinia enterocolitica is an extracellular pathogen and its related antigens interact with the host immune system. We investigated the difference in immunological characteristics between a highly pathogenic and poorly pathogenic strain of Y. enterocolitico. Methods We used SDS-PAGE and western blotting to characterize lipopolysaccharide （LPS）, Yersinio outer membrane proteins （Yops）, membrane proteins, and whole-cell proteins from poorly pathogenic Y. enterocolitico bio-serotype 2/0：9, isolated from China, and highly pathogenic bio-serotype 1B/O：8, isolated from Japan. Results These two strains of Y. enterocolitica had different LPS immune response patterns. Comparison of their Yops also showed differences that could have accounted for their differences in pathogenicity. The membrane and whole-cell proteins of both strains were similar; immunoblottting showed that the 35 kD and perhaps the 10 kD proteins were immunogens in both strains. Conclusion The major antigens of the two strains e and membrane proteins, as shown by comparing preparations. citing the host immune protein samples with response were the LPS reference and purified

关键词： Immunogens Lipopolysaccharides outer membrane proteins Whole-cell proteins Pathogenic Yersinia enterocolitica

The folding of OmpT into Tween 20

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The folding of OmpT into Tween 20

第十届全国化学生物学学术会议

作者： Chenhui He Peixuan Bu Xin Sheng Zhao Biodynamic Optical Imaging Center (BIOPIC) Peking University School of Life Sciences Peking University College of Chemistry and Molecular Engineering Peking University

β-barrel outer membrane proteins（OMPs） are involved in a number of key life processes of Gram-negative bacteria, and some of the OMPs are also related to the pathogenicity and drug resistance of the bacteria1. Therefore, the study of the biogenesis of OMPs will provide theoretical support for new antimicrobial drugs. Folding of OMPs has been studied extensively in vitro, however, the exact molecular mechanism that is involved remains elusive. We selected OmpT as a model OMPs to study OMPs folding in detergents. We showed that OmpT could form a stable structure with its protease activity in both DDM and Tween 20. The single molecule FRET experiments implied that the folded structure of OmpT into Tween 20 is similar to the natural structure. Folded OmpT had different stability in different detergents, manifested by the tolerance to urea and the interaction with SurA. These differences could be due to the structures of folded OmpT in various detergents, or the interaction between OmpT and the detergent molecules. Previously Tween 20 was often used to stabilize proteins in aqueous solution. Our results suggest that caution should be taken to avoid possible artifact when Tween 20 was added to OMPs solution.

关键词： outer membrane proteins Folding Single molecular FRET DDM Tween 20

The conformation of SurA-OMP complex

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The conformation of SurA-OMP complex

中国化学会第五届全国生物物理化学会议（NCBPC5）

作者：何晨辉 Geng Li Xin Sheng Zhao Biodynamic Optical Imaging Center (BIOPIC) Peking University School of Life Sciences Peking University College of Chemistry and Molecular Engineering Peking University

β-barrel outer membrane proteins（OMPs） are involved in a number of key life processes of Gram-negative *** are synthesized in the cytoplasm and thus have to be transported across the inner membrane,through the periplasm and into the outer *** ***,several chaperones have been identified to play a role in the transit of OMPs through the *** is a major chaperone protein that facilitates maturation of OMPs and transfers its substrate OMPs to the BAM complex.3 To understand the delivery process,it is very important to obtain the conformation of SurA-OMP *** using FRET technique,we studied the conformation of the SurA-OMP *** binding to SurA,OmpC shows a lower FRET *** distances between residues in all OmpC mutants（G8C/N336C,G8C/L139C,L139C/F269C,and I232C/N336C） changed gradually around the turning point as the urea concentration *** caused all parts of OmpC to expand to the same extent,indicating that when binding to SurA,OmpC behaves like a random *** was difficult to obtain the conformations of SurA in the SurA-OmpC complex,because it was hard to distinguish the SurA-OmpC complex from the free *** it was important to obtain the pure SurA-OmpC *** tried to crosslink OmpC and SurA by ***,we optimized the crosslinking conditions to obtain more SurA-OmpC *** we separated the crosslinked SurA-OmpC complex from the self-crosslinked products by SDS-PAGE and gel *** result showed that SurA became a bit looser after binding with *** the basis of the observation,a model on the conformation of the SurA-OmpC complex was proposed.

关键词： outer membrane proteins SurA FRET Single molecule

Analysis of Immunological Activity of Recombinant outer membrane Protein of Fusobacterium Necrophorum

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Analysis of Immunological Activity of Recombinant Outer Memb...

作者： Hang Jia Shengxin Wang Xiaoli Zhang Yang Guo Jing Xu Medical Laboratory Technology College of Medical Technology Qiqihar Medical University Department of Biochemistry and Molecular Biology Qiqihar Medical University

To investigate the prokaryotic expression of 93 ku outer membrane protein（OMP） obtained from Fusobacterium necrophorum and the response to immunization and cytotoxicity in mice. The recombinant plasmid pET-28 a-OMP was transformed into E. coli BL21（DE3） competent form, and a recombinant outer membrane protein containing 2 His tags（label size 3.8 ku） was expressed. The mice were immunized as immunization antigens by Freund’s incomplete adjuvant. SDS-PAGE and Western blot analysis showed that the recombinant protein had a molecular weight of about 93 ku. After the immunization, the serum antibody titer of the experimental group was higher, at the same time, in the challenge experiment, the liver has certain toxicity, and the protection rate is 83.3%. The recombinant 93 ku outer membrane protein of Fusobacterium necrophorum has a good immune response level and provides basic data for the study of the subunit vaccine of Fusobacterium necrophorum.

关键词： Fusobacterium necrophorum outer membrane proteins Immunoprotective

Prevalence and mechanisms of carbapenems-resistance in Enterobacteriaceae with decreased susceptibility to carbapenem,in Zhejiang Province

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Prevalence and mechanisms of carbapenems-resistance in Enter...

2012年浙江省检验医学学术年会

作者： Yamin Lu Xiaolei Zhang Tieli Zhou Meiyan Guo Jianbo Ye Qiyue Bao Wenjie Chi Department of Clinical Laboratory the First Affiliated Hospital of Wenzhou Medical College

Enterobacteriaceae are the most frequently encountered nosocomial pathogens. Carbapenems are frequently the only therapeutic options available for treatment of serious nosocomial infections caused by multidrug-resistant Enterobacteriaceae clinical ***,carbapenem resistance in Enterobacteriaceae is increasing and has become a matter of great *** present study, we investigated the prevalence and mechanisms of carbapenem resistance in Enterobacteriaceae clinical *** Enterobacteriaceae clinical isolates showing decreased susceptibility to carbapenems recovered in 2007 - 2010 from different hospitals in Zhejiang province were investigated for the mechanisms of carbapenem *** resistance rate of imipenem,meropenem and ertapenem were 52.6%,35.1%and 82.5%,*** and sequencing experiments detected carbapenemase genes in 32 of 70 isolates,furthermore,AmpCβ-lactamase genes and bla genes of extended-spectrumβ-lactamases were also detected in 18 and 10 of 70 clinical isolates,*** experiments showed that carbapenemase genes of 8 isolates out of 32 carbapenemase-producing isolates were carried by conjugative *** dodecyl sulfatepolyacrylamide gel electrophoresis(SDSPAGE) experiments indicated that 33.3%(19/57) of isolates had lost porin ***-field gel electrophoresis(PFGE) analysis demonstrated that 9 KPC-2-producing Serratia marcescens belonged to a clonal strain and 8 strains were isolated from the same ward,namely Intensive Care Unit(ICU), suggesting a horizontal spread of KPC-2 in these *** study confirmed multiple mechanisms of carbapenem resistance in Enterobacteriaceae clinical isolates:the high level carbapenems resistance in Klebsiella pneumoniae,Citrobacter freundii and Serratin marcescens is mostly mediated by carbapenemase production,however,low susceptibility to imipenem in Morganella morganii is mostly due to AmpC enzyme hyperproduction,furthermore,ertapenem resis

关键词： Enterobacteriaceae Carbapenem-resistant Carbapenemase outer membrane proteins Resistance mechanisms