1,721,070 research outputs found
Molecular Dynamics Simulations of A * T-Rich Oligomers: Sequence- Specific Binding of Na+ in the Minor Groove of B-DNA
No full textMolecular dynamics simulations have been employed to probe the sequence-specific binding of sodium ions to the minor groove of B-DNA of three A . T-rich oligomers having identical compositions but different orders of the base pairs: C(AT)(4)G, CA(4)T(4)G, and CT(4)A(4)G. Recent experimental investigations, either in crystals or in solution, have shown that monovalent cations bind to DNA in a sequence-specific mode, preferentially in the narrow minor groove regions of uninterrupted sequences of four or more adenines (A-tracts), replacing a water molecule of the ordered hydration structure, the hydration spine. Following this evidence, it has been hypothesized that in A-tracts these events may be responsible for structural peculiarities such as a narrow minor groove and a curvature of the helix axis. The present simulations confirm a sequence specificity of the binding of sodium ions: Na+ intrusions in the first layer of hydration of the minor groove, with long residence times, up to similar to3 ns, are observed only in the minor groove of A-tracts but not in the alternating sequence. The effects of these intrusions on the structure of DNA depend on the ion coordination: when the ion replaces a water molecule of the spine, the minor groove becomes narrower. Ion intrusions may also disrupt the hydration spine modifying the oligomer structure to a large extent. However, in no case intrusions were observed to locally bend the axis toward the minor groove. The simulations also show that ions may reside for long time periods in the second layer of hydration, particularly in the wider regions of the groove, often leading to an opening of the groove. (C) 2003 Wiley Periodicals, Inc
Studi offerti a Mario Atzori. Etnografie in dialogo: curiosità e passioni
No full textNel volume confluiscono studi di colleghi, amici e allievi che si sono ritrovati per porgere un omaggio a Mario Atzori, un segno di riconoscenza per il lavoro che il Professore ha svolto sia in ambito accademico sia al di fuori del contesto universitario
Archeologia e storia della pluriattività in età contemporanea. Lavoro stagionale e strutture produttive nelle fornaci laterizie preindustriali della Sardegna
No full textLa Sardegna terra d'esilio. Dall'esilio politico in età imperiale all'esilio per fede nel cristianesimo
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Dynamical properties of ATP/CdCl2 and ATP/Cd(ClO4)2 complexes: a combined 13C and 113Cd relaxation study.
No full textC-13 magnetic relaxation rates of Fe(III) complexes of some biogenic amines and parent compounds in aqueous solutions
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