In:
Zeitschrift für Naturforschung C, Walter de Gruyter GmbH, Vol. 37, No. 9 ( 1982-9-1), p. 824-832
Abstract:
The binding of Hg 2+ and 3,6-bis-(acetatomercurimethyl)-dioxane (BAMD) to sonicated calf thymus DNA was studied by small-angle X-ray scattering and viscosity measurements. The scattering experiments with DNA complexed by different amounts of mercurials (for Hg 2+ r b = 0-0.79, for BAMD r b = 0-0.86 mol of mercurial bound per mol of base pairs) established that the rod-like character of the DNA molecules is maintained up to high binding ratios. They revealed further a steady decrease of the cross-section radius of gyration R c for the DNA · Hg 2+ complex and a similar decrease of R c for the DNA · BAMD complex up to r b = 0.35. This behaviour is certainly caused by the incorporation of both mercurials near the axis of the DNA helix. Binding of BAMD at r b 〉 0.35 led to an increase of R c which behaviour obviously reflects the location of mercury atoms at large distances from the axis, possibly on the surface of the helix. The increase of the mass per unit length M c upon binding of the mercurials was found to be much higher than expected. This finding established that the length of the DNA helix decreases by 0.10±0.01 nm per bound mercurial at low binding ratios (i.e. up to r b = 1/3 for BAMD, up to possibly r b = 0.5 for Hg 2+ ). A similar conclusion was also drawn from the observed decrease of intrinsic viscosity [rj] with increasing r b . The analysis of M c at high binding ratios suggests that every BAMD molecule bound beyond r b =1/3 decreases the length of the DNA by 0.21 ±0.05 nm whereas Hg 2+ when bound beyond r b = 0.5 causes no change of the length.
Type of Medium:
Online Resource
ISSN:
1865-7125
,
0939-5075
DOI:
10.1515/znc-1982-0915
Language:
English
Publisher:
Walter de Gruyter GmbH
Publication Date:
1982
detail.hit.zdb_id:
2078107-6
SSG:
12
Permalink