Three-dimensional solution structure, backbone dynamics and RNA binding properties of Mason-Pfizer monkey virus nucleocapsid protein /
Retroviral nucleocapsid proteins (NCPs) are CCHC-type zinc finger proteins which mediate virion RNA binding activities associated with retrofits assembly and genomic RNA encapsulation. Mason-Pfizer monkey virus (MPMV) encodes a 96-amino acid nucleocapsid protein, which contains two Cys-X₂-Cys-X₄-His...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1999.
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| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=733671271&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | Retroviral nucleocapsid proteins (NCPs) are CCHC-type zinc finger proteins which mediate virion RNA binding activities associated with retrofits assembly and genomic RNA encapsulation. Mason-Pfizer monkey virus (MPMV) encodes a 96-amino acid nucleocapsid protein, which contains two Cys-X₂-Cys-X₄-His-X₄-Cys (CCHC) zinc Embers. Three-dimensional structural calculations based on NMR experiments of the core domain of MPMV NCP encompassing residues 21-80 suggest that the N-terminal and C-terminal zinc fingers of MPMV NCP adopt a similar overall fold of a ''zinc knuckle'' structure, like that of other previously studied NCP domains. However, the C- terminal anger domain of MPMV NCP contains additional stable structure, with residues that follow the CCHC array folded into a reverse turn that packs against the core finger. Backbone dynamics studies reveal that MPMV NCP 21-80 is best described as two independently folded, rotationally uncorrelated globular domains connected by a flexible linker consisting of residues 42-48. Fluorescence and isothermal titration calorimetry (ITC) binding experiments carried out on both intact MPMV NCP and NCP 21-80 suggest that terminal regions play important roles in modulating the RNA binding properties of the protein. ITC experiments carried out with a GNRA-type tetraloop RNA provide evidence of binding complex heterogeneity, with distinct 1:2, 1:1 and 2:1 NCP:RNA complexes detectable in solution. Perturbation of the ¹⁵N-¹H HSQC spectrum of uniformly ¹⁵N labeled NCP upon titration with different small RNAs suggests that a subset of residues within each of the two finger region, especially those close to the aromatic residues, become significantly perturbed upon RNA binding while those within the linker region and in the C-terminal tail region are not directly involved in RNA binding. Overall, our RNA binding experiments suggest the possibility that MPMV NCP, and by extension other retrofire NCPS, are capable of forming a number of structurally distinct, but energetically similar, complexes which dicer in both macroscopic and microscopic details. These structural, dynamics and RNA binding properties provide molecular insight into the functional properties of processed NCP in retroviral replication.
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| Item Description: | Vita. "Major Subject: Biochemistry". |
| Physical Description: | xiii, 162 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilm Inc. |
| Bibliography: | Includes bibliographical references (leaves 148-160). |