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'Methylmercury Complexes' in keywords
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1979 (2)
1Author    DieterW. Gruenwedel, SusanE. BrownRequires cookie*
 Abstract    Single-stranded and methylmercurated T7 DNA is com­ posed of two species as evidenced from the sedimentation pattern displayed during band-sedimentation in self-generat­ ing density gradients as well as during equilibrium-sedi-mentation in Cs2S 0 4 density gradients. Under the given experimental conditions, viz., at pH 9.18 and in presence of 0.1 mM CH3HgOH, the two species band in Cs2S 0 4 with a density difference of 0.008 g/ml. The ratio of the sedimenta­ tion coefficients of the two species is Sw, 20 (fast) Jsw, 20 (slow) = 1.63 at pH 9.18 and in presence of 1.6 mM CH3HgOH. Both native and denatured T7 DNA behave as monodis-perse systems in the absence of CH3HgOH. 
  Reference    Z. Naturforsch. 34c, 162 (1979); received September 21 1978 
  Published    1979 
  Keywords    Sedimentation Heterogeneity, T7 DNA, Methylmercury Complexes 
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 TEI-XML for    default:Reihe_C/34/ZNC-1979-34c-0162_n.pdf 
 Identifier    ZNC-1979-34c-0162_n 
 Volume    34 
2Author    MichaelS. Clegg, DieterW. GruenwedelRequires cookie*
 Title    Circular Dichroism and Ultraviolet Absorbance of Calf Thymus D NA in Presence of C H 3HgOH  
 Abstract    The changes that one observes upon the addition of CH3HgOH in the circular dichroism spec­ trum and ultraviolet absorbance spectrum of native calf thymus DNA, dissolved in buffered (pH 6.8) solutions of Na2S04 at pNa 2.0, 1.5, 1.0, and 0.0, respectively (p N a = —log [Na+ ]), are shown to be due to denaturation brought about by the organomercurial interacting with the base moieties of the polymer. The changes are characterized by an extensive shift of both spectra to longer wavelengths, by a decrease of the rotational strength of the long-wavelength positive dichroic absorption band, and by an increase in the UV absorbance at l max • Both the hyperchromicity H * of calf thymus DNA and the normalized decrease of the rotational strength of its long-wavelength positive dichromic band, Q , display cooperativity when plotted against the methylmercury concentra­ tion pM (p M = — log [CH3HgOH] a dde d) at a given salt strength. Rotational strength data, eval­ uated by integration of the area under the positive and negative dichroic absorption bands, have been tabulated for selected values of pNa and pM. They are compared with data available from the literature. In absence of CH3HgOH, and with varying salt strength, native calf thymus DNA exhibits alterations in the long-wavelength positive dichroic absorption band that are interpreted as representing B — * ■ C transitions in agreement with currently held views regarding their origin. Similar salt-induced alterations have been noted in the case of denatured DNA; their meaning in terms of DNA geometry remains unclear at this point in time. 
  Reference    Z. Naturforsch. 34c, 259—265 (1979); received November 27 1978 
  Published    1979 
  Keywords    Circular Dichroism, Ultraviolet Absorbance, Calf Thymus DNA, Methylmercury Complexes, Denaturation 
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 TEI-XML for    default:Reihe_C/34/ZNC-1979-34c-0259.pdf 
 Identifier    ZNC-1979-34c-0259 
 Volume    34