Sarah C. Keane

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The 5' leader of the HIV-1 genome contains conserved elements that direct selective packaging of the unspliced, dimeric viral RNA into assembling particles. By using a (2)H-edited nuclear magnetic resonance (NMR) approach, we determined the structure of a 155-nucleotide region of the leader that is independently capable of directing packaging (core(More)
All coronaviruses (CoVs), including the causative agent of severe acute respiratory syndrome (SARS), encode a nucleocapsid (N) protein that harbors two independent RNA binding domains of known structure, but poorly characterized RNA binding properties. We show here that the N-terminal domain (NTD) of N protein from mouse hepatitis virus (MHV), a virus most(More)
Coronaviruses (CoVs) are positive-sense, single-stranded, enveloped RNA viruses that infect a variety of vertebrate hosts. The CoV nucleocapsid (N) protein contains two structurally independent RNA binding domains, designated the N-terminal domain (NTD) and the dimeric C-terminal domain (CTD), joined by a charged linker region rich in serine and arginine(More)
Coronavirus (CoV) nucleocapsid (N) protein contains two structurally independent RNA binding domains. These are denoted N-terminal domain (NTD) and C-terminal domain and are joined by a charged linker region rich in serine and arginine residues (SR linker). In mouse hepatitis virus (MHV), the NTD binds the transcriptional regulatory sequence (TRS) RNA, a(More)
HIV type-1 (HIV-1) contains a pseudodiploid RNA genome that is selected for packaging and maintained in virions as a noncovalently linked dimer. Genome dimerization is mediated by conserved elements within the 5'-leader of the RNA, including a palindromic dimer initiation signal (DIS) that has been proposed to form kissing hairpin and/or extended duplex(More)
Stem-loop 2 (SL2) of the 5'-untranslated region of the mouse hepatitis virus (MHV) contains a highly conserved pentaloop (C47-U48-U49-G50-U51) stacked on a 5-bp stem. Solution nuclear magnetic resonance experiments are consistent with a 5'-uYNMG(U)a or uCUYG(U)a tetraloop conformation characterized by an anti-C47-syn-G50 base-pairing interaction, with U51(More)
Isotope labeling has revolutionized NMR studies of small nucleic acids, but to extend this technology to larger RNAs, site-specific labeling tools to expedite NMR structural and dynamics studies are required. Using enzymes from the pentose phosphate pathway, we coupled chemically synthesized uracil nucleobase with specifically (13) C-labeled ribose to(More)
HIV-1 Gag selects and packages a dimeric, unspliced viral RNA in the context of a large excess of cytosolic human RNAs. As Gag assembles on the plasma membrane, the HIV-1 genome is enriched relative to cellular RNAs by an unknown mechanism. We used a minimal system consisting of purified RNAs, recombinant HIV-1 Gag and giant unilamellar vesicles to(More)
Nonstructural protein (nsp) 3 is the largest of 16 nsps translated from the murine hepatitis virus (MHV) genome. The N-terminal most domain of nsp3, nsp3a, has been identified by reverse genetics as a likely binding partner of MHV nucleocapsid protein. Here we report the backbone and side chain resonance assignments of MHV nsp3a (residues 1-114).