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  • Proceedings of the National Academy of Sciences  (4)
  • 1
    Online Resource
    Online Resource
    Proceedings of the National Academy of Sciences ; 2019
    In:  Proceedings of the National Academy of Sciences Vol. 116, No. 25 ( 2019-06-18), p. 12343-12352
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 116, No. 25 ( 2019-06-18), p. 12343-12352
    Abstract: Genes encoding cytochrome P450 (CYP; P450) enzymes occur widely in the Archaea, Bacteria, and Eukarya, where they play important roles in metabolism of endogenous regulatory molecules and exogenous chemicals. We now report that genes for multiple and unique P450s occur commonly in giant viruses in the Mimiviridae , Pandoraviridae , and other families in the proposed order Megavirales. P450 genes were also identified in a herpesvirus ( Ranid herpesvirus 3 ) and a phage ( Mycobacterium phage Adler). The Adler phage P450 was classified as CYP102L1, and the crystal structure of the open form was solved at 2.5 Å. Genes encoding known redox partners for P450s (cytochrome P450 reductase, ferredoxin and ferredoxin reductase, and flavodoxin and flavodoxin reductase) were not found in any viral genome so far described, implying that host redox partners may drive viral P450 activities. Giant virus P450 proteins share no more than 25% identity with the P450 gene products we identified in Acanthamoeba castellanii , an amoeba host for many giant viruses. Thus, the origin of the unique P450 genes in giant viruses remains unknown. If giant virus P450 genes were acquired from a host, we suggest it could have been from an as yet unknown and possibly ancient host. These studies expand the horizon in the evolution and diversity of the enormously important P450 superfamily. Determining the origin and function of P450s in giant viruses may help to discern the origin of the giant viruses themselves.
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
    RVK:
    RVK:
    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 2019
    detail.hit.zdb_id: 209104-5
    detail.hit.zdb_id: 1461794-8
    SSG: 11
    SSG: 12
    Location Call Number Limitation Availability
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  • 2
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 111, No. 26 ( 2014-07), p. 9609-9614
    Abstract: Restriction factors (RFs) form important components of host defenses to retroviral infection. The Fv1, Trim5α, and TrimCyp RFs contain N-terminal dimerization and C-terminal specificity domains that target assembled retroviral capsid (CA) proteins enclosing the viral core. However, the molecular detail of the interaction between RFs and their CA targets is unknown. Therefore, we have determined the crystal structure of the B-box and coiled-coil (BCC) region from Trim5α and used small-angle X-ray scattering to examine the solution structure of Trim5α BCC, the dimerization domain of Fv1 (Fv1Ntd), and the hybrid restriction factor Fv1Cyp comprising Fv1NtD fused to the HIV-1 binding protein Cyclophilin A (CypA). These data reveal that coiled-coil regions of Fv1 and Trim5α form extended antiparallel dimers. In Fv1Cyp, two CypA moieties are located at opposing ends, creating a molecule with a dumbbell appearance. In Trim5α, the B-boxes are located at either end of the coiled-coil, held in place by interactions with a helical motif from the L2 region of the opposing monomer. A comparative analysis of Fv1Cyp and CypA binding to a preformed HIV-1 CA lattice reveals how RF dimerization enhances the affinity of interaction through avidity effects. We conclude that the antiparallel organization of the NtD regions of Fv1 and Trim5α dimers correctly positions C-terminal specificity and N-terminal effector domains and facilitates stable binding to adjacent CA hexamers in viral cores.
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
    RVK:
    RVK:
    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 2014
    detail.hit.zdb_id: 209104-5
    detail.hit.zdb_id: 1461794-8
    SSG: 11
    SSG: 12
    Location Call Number Limitation Availability
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  • 3
    Online Resource
    Online Resource
    Proceedings of the National Academy of Sciences ; 2011
    In:  Proceedings of the National Academy of Sciences Vol. 108, No. 14 ( 2011-04-05), p. 5771-5776
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 108, No. 14 ( 2011-04-05), p. 5771-5776
    Abstract: The restriction factor Fv1 confers resistance to murine leukemia virus (MLV), blocking progression of the viral life cycle after reverse transcription, but before integration into the host chromosome. It is known that the specificity of restriction is determined by both the restriction factor and the viral capsid (CA), but a direct interaction between Fv1 and MLV CA has not yet been demonstrated. With the development of a previously unexplored method for in vitro polymerization of MLV CA, it has now been possible to display a binding interaction between Fv1 and MLV CA. C-terminally His-tagged CA molecules were assembled on Ni-chelating lipid nanotubes, and analysis by electron microscopy revealed the formation of a regular lattice. Comparison of binding data with existing restriction data confirmed the specificity of the binding interaction, with multiple positions of both Fv1 and CA shown to influence binding specificity.
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
    RVK:
    RVK:
    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 2011
    detail.hit.zdb_id: 209104-5
    detail.hit.zdb_id: 1461794-8
    SSG: 11
    SSG: 12
    Location Call Number Limitation Availability
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  • 4
    Online Resource
    Online Resource
    Proceedings of the National Academy of Sciences ; 2001
    In:  Proceedings of the National Academy of Sciences Vol. 98, No. 17 ( 2001-08-14), p. 9551-9556
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 98, No. 17 ( 2001-08-14), p. 9551-9556
    Abstract: The correct formation of disulfide bonds in the periplasm of Escherichia coli involves Dsb proteins, including two related periplasmic disulfide-bond isomerases, DsbC and DsbG. DsbD is a membrane protein required to maintain the functional oxidation state of DsbC and DsbG. In this work, purified proteins were used to investigate the interaction between DsbD and DsbC. A 131-residue N-terminal fragment of DsbD (DsbDα) was expressed and purified and shown to form a functional folded domain. Gel filtration results indicate that DsbDα is monomeric. DsbDα was shown to interact directly with and to reduce the DsbC dimer, thus increasing the isomerase activity of DsbC. The DsbC–DsbDα complex was characterized, and formation of the complex was shown to require the N-terminal dimerization domain of DsbC. These results demonstrate that DsbD interacts directly with full-length DsbC and imply that no other periplasmic components are required to maintain DsbC in the functional reduced state.
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
    RVK:
    RVK:
    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 2001
    detail.hit.zdb_id: 209104-5
    detail.hit.zdb_id: 1461794-8
    SSG: 11
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
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