The nueleocapsid (N) protein of severe acute respiratory syndrome-coronavirus (SARS-CoV) is a major virion structural protein. In this study, two epitopes (Nl and N2) of the N protein of SARS-CoV were predicted by bio...The nueleocapsid (N) protein of severe acute respiratory syndrome-coronavirus (SARS-CoV) is a major virion structural protein. In this study, two epitopes (Nl and N2) of the N protein of SARS-CoV were predicted by bioinformatics analysis. After immunization with two peptides, the peptides-specific antibodies were isolated from the immunized rabbits. The further experiments demonstrated that N1 peptide-induced polyclonal antibodies had a high affinity to bind to E. coli expressed N protein of SAR,S-CoV. Furthermore, it was confirmed that Nl peptide-specific IgG antibodies were detectable in the sera of severe acute respiratory syndrome (SARS) patients. The results indicated that an epitope of the N protein has been identified and N protein specific Abs were produced by peptide immunization, which will be useful for the study of SARS-CoV.展开更多
The antigenic determinants of trichosanthin were predicted by molecular modeling. First, the threedimensional structure model of the antigen-binding fragment of anti-trichosanthin immunoglobulin E was built on the bas...The antigenic determinants of trichosanthin were predicted by molecular modeling. First, the threedimensional structure model of the antigen-binding fragment of anti-trichosanthin immunoglobulin E was built on the basis of its amino-acid sequence and the known three-dimensional structure of an antibody with similar sequence. Secondly, the preferable antigen-antibody interactions were obtained based on the known three-dimensional structure of trichosanthin and of the hypervariable regions of anti-trichosanthin immunoglobulin E. Two regions in the molecular surface of trichosanthin were found to form extensive interactions with the hypervariable regions of the antibody and have been predicted to be the possible antigenic determinants: one is composed of two polypeptide segments, Ile201-Glu210 and Ile225-Asp229, which are close to each other in the three-dimensional structure; and the other is the segment Lys173-Thr178. The former region seems to be the more reasonable antigenic determinant than the latter one.展开更多
Beauvericin, a cyclohexadepsipeptide-possessing natural product with synergistic antifungal, insecticidal, and cytotoxic activities. We isolated and characterized the fpBeas gene cluster, devoted to beauvericin biosyn...Beauvericin, a cyclohexadepsipeptide-possessing natural product with synergistic antifungal, insecticidal, and cytotoxic activities. We isolated and characterized the fpBeas gene cluster, devoted to beauvericin biosynthesis, from the filamentous fungus Fusarium proliferatum LF061. Targeted inactivation of the F. proliferatum genomic copy of fpBeas abolished the production of beauvericin. Comparative sequence analysis of the FpBEAS showed 74% similarity with the BbBEAS that synthesizes the cyclic trimeric ester beauvericin in Beauveria bassiana, which assembles N-methyl-dipeptidol monomer intermediates by the programmed iterative use of the nonribosomal peptide synthetase modules. Differences between the organization of the beauvericin loci in F. proliferaturm and B. bassiana revealed the mechanism for high production of beauvericin in F. proliferatum. Our work provides new insights into beauvericin biosynthesis, and may lead to beauvericin overproduction and creation of new analogs via synthetic biology approaches.展开更多
基金supported by the grant of Shanghai Science and Technology Committee(No.03DZ19113)National Key Basic Research Program of China(No.2001CB510006)+1 种基金863 project(No.2001AA231011)a specific project against SARS from Chinese Academy of Sciences.
文摘The nueleocapsid (N) protein of severe acute respiratory syndrome-coronavirus (SARS-CoV) is a major virion structural protein. In this study, two epitopes (Nl and N2) of the N protein of SARS-CoV were predicted by bioinformatics analysis. After immunization with two peptides, the peptides-specific antibodies were isolated from the immunized rabbits. The further experiments demonstrated that N1 peptide-induced polyclonal antibodies had a high affinity to bind to E. coli expressed N protein of SAR,S-CoV. Furthermore, it was confirmed that Nl peptide-specific IgG antibodies were detectable in the sera of severe acute respiratory syndrome (SARS) patients. The results indicated that an epitope of the N protein has been identified and N protein specific Abs were produced by peptide immunization, which will be useful for the study of SARS-CoV.
文摘The antigenic determinants of trichosanthin were predicted by molecular modeling. First, the threedimensional structure model of the antigen-binding fragment of anti-trichosanthin immunoglobulin E was built on the basis of its amino-acid sequence and the known three-dimensional structure of an antibody with similar sequence. Secondly, the preferable antigen-antibody interactions were obtained based on the known three-dimensional structure of trichosanthin and of the hypervariable regions of anti-trichosanthin immunoglobulin E. Two regions in the molecular surface of trichosanthin were found to form extensive interactions with the hypervariable regions of the antibody and have been predicted to be the possible antigenic determinants: one is composed of two polypeptide segments, Ile201-Glu210 and Ile225-Asp229, which are close to each other in the three-dimensional structure; and the other is the segment Lys173-Thr178. The former region seems to be the more reasonable antigenic determinant than the latter one.
基金supported by the National Basic Research Program of China (2013CB734000, 2012CB725200)the CAS Pillar Program (XDA04074000)+1 种基金Ministry of Science and Technology of China (2011ZX11102-011-11)ZHANG LiXin is an Awardee for the National Distinguished Young Scholar Program in China
文摘Beauvericin, a cyclohexadepsipeptide-possessing natural product with synergistic antifungal, insecticidal, and cytotoxic activities. We isolated and characterized the fpBeas gene cluster, devoted to beauvericin biosynthesis, from the filamentous fungus Fusarium proliferatum LF061. Targeted inactivation of the F. proliferatum genomic copy of fpBeas abolished the production of beauvericin. Comparative sequence analysis of the FpBEAS showed 74% similarity with the BbBEAS that synthesizes the cyclic trimeric ester beauvericin in Beauveria bassiana, which assembles N-methyl-dipeptidol monomer intermediates by the programmed iterative use of the nonribosomal peptide synthetase modules. Differences between the organization of the beauvericin loci in F. proliferaturm and B. bassiana revealed the mechanism for high production of beauvericin in F. proliferatum. Our work provides new insights into beauvericin biosynthesis, and may lead to beauvericin overproduction and creation of new analogs via synthetic biology approaches.
