An analogue of the DNA-binding compound Hoechst 33258, in which the piperazine ring has been replaced by an imidazoline group, has been cocrystallized with the dodecanucleotide sequence ...d(CGCGAATTCGCG)2. The structure has been solved by X-ray diffraction analysis and has been refined to an R-factor of 19.7% at a resolution of 2.0 Å. The ligand is found to bind in the minor groove, at the central four AATT base pairs of the B-DNA double helix, with the Involvement of a number of van der Waals contacts and hydrogen bonds. There are significant differences in minor groove width for the two compounds, along much of the AATT region. in particular this structure shows a narrower groove at the 3′ end of the binding site consistent with the narrower cross-section of the imidazole group compared with the piperazine ring of Hoechst 33258 and therefore a smaller perturbation in groove width. The higher binding affinity to DNA shown by this analogue compared with Hoechst 33258 itself, has been rationalised in terms of these differences.
The structure of the B-DNA decamer d(CGCAATTGCG)2 has been determined by X-ray diffraction analysis to a resolution of 2.3 A and an R-factor of 17.7%. The decamer crystallises in the monoclinic space ...group C2 and packs with a crossed arrangement of helices and a unique crossing contact distinct from all other decamer structures. This is believed to be a direct result of the sequence-dependent minor groove width of the duplex. Crossed helix structures of DNA are valuable starting points for modelling studies of the Holliday junction. Two unique sites are observed at the cross-over junction where strand exchange may occur. A Holliday junction model has been constructed for each case and modelled using molecular mechanics and dynamics techniques. One of these models was found to be fully consistent with the available physical data.
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IJS, IMTLJ, KILJ, KISLJ, NUK, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The bright and understudied classical Be star HD 6226 has exhibited multiple outbursts in the last several years during which the star grew a viscous decretion disk. We analyze 659 optical spectra of ...the system collected from 2017-2020, along with a UV spectrum from the Hubble Space Telescope and high cadence photometry from both TESS and the KELT survey. We find that the star has a spectral type of B2.5IIIe, with a rotation rate of 74% of critical. The star is nearly pole-on with an inclination of \(13.4\) degree. We confirm the spectroscopic pulsational properties previously reported, and report on three photometric oscillations from KELT photometry. The outbursting behavior is studied with equivalent width measurements of H\(\alpha\) and H\(\beta\), and the variations in both of these can be quantitatively explained with two frequencies through a Fourier analysis. One of the frequencies for the emission outbursts is equal to the difference between two photometric oscillations, linking these pulsation modes to the mass ejection mechanism for some outbursts. During the TESS observation time period of 2019 October 7 to 2019 November 2, the star was building a disk. With a large dataset of H\(\alpha\) and H\(\beta\) spectroscopy, we are able to determine the timescales of dissipation in both of these lines, similar to past work on Be stars that has been done with optical photometry. HD 6226 is an ideal target with which to study the Be disk-evolution given its apparent periodic nature, allowing for targeted observations with other facilities in the future.
The pp52 gene encodes an intracellular, F-actin-binding phosphoprotein (also designated LSP1 and WP34) postulated to function in cytoskeleton dynamics and cell motility. We previously reported that ...different mRNA isoforms are expressed from this gene in cells of the leukocyte lineage versus mesodermally derived cells. These tissue-specific mRNA isoforms are identical except for 5′-untranslated regions and sequences coding for unique N-termini of 23 and 21 amino acids, respectively. As this is a single-copy gene, we predicted that these tissue-specific mRNA isoforms would be generated by alternative RNA splicing. We report that the unique 5′ sequences in these mRNA isoforms are encoded in two separate exons containing ATG initiation codons. These features confirm that the pp52 and S37 mRNA isoforms are generated by alternative RNA splicing and establish that they are independently translated. Other results presented here indicate that the differential expression of these exons in leukocytes versus mesodermally derived cells is regulated at the level of transcription by tissue-specific promoters.
The B29 gene encodes a B-cell-specific membrane protein in the immunoglobulin antigen receptor complex. B29 is a crucial member of this receptor complex and is believed to function as an effector of ...signal transduction in a manner analogous to that of the CD3 components of the T cell antigen receptor. We have isolated a full-length human B29 cDNA clone by using a murine B29 cDNA probe. We show that there is an extremely high degree of evolutionary conservation between the human and mouse proteins, particularly in the transmembrane and intracytoplasmic regions, where the identity is 96%. In addition, the intracytoplasmic region in both proteins contains an identical peptide motif that is present in a number of molecules involved in lymphocyte activation. Genomic Southern blot analysis of human cell lines hybridized with both murine and human B29 cDNAs gives patterns consistent with a single-copy gene occupying a small region of the genomic sequence. Using human B29 cosmid DNA, we have localized the B29 gene to human chromosome 17q23 via fluorescence in situ hybridization. B29 is the first gene localized to this area of the genome. Interestingly, a subset of human B cell chronic lymphocytic leukemias (CLL) has translocations in this locus on chromosome 17.
Understanding the process of bereavement among former caregivers to the elderly will enable practitioners to offer support more effectively. This study examines bereavement among 38 daughters who ...were caregivers to their elderly mothers. Comparing bereavement feelings at 2 months to feelings at 6 months following the mother's death, daughters reported decreases in grief resolution behaviors and feelings of emotional shock, anger, and helplessness. Comparison to elderly widows indicated similarities in reported rates of most bereavement feelings at 2 and 6 months. Depression rates measured by the CES-D were not elevated for bereaved daughters. Implications for practice are discussed.
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BFBNIB, INZLJ, NMLJ, NUK, ODKLJ, PNG, SAZU, UL, UM, UPUK, ZRSKP
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