Conformational changes of the chromatin subunit
Hydrodynamic studies on monomer chromatin subunits (ν1) as a function of ionic strength (0.7 mM to 100 mM KCl) indicate two salt-dependent conformational transitions. An abrupt transition occurs at about 7.5 mM ionic strength. Decreasing the ionic strength from 10 to 5 mM results in a decrease in s2...
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Published in | Proceedings of the National Academy of Sciences - PNAS Vol. 75; no. 2; pp. 660 - 663 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
United States
National Academy of Sciences of the United States of America
01.02.1978
National Acad Sciences |
Subjects | |
Online Access | Get full text |
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Summary: | Hydrodynamic studies on monomer chromatin subunits (ν1) as a function of ionic strength (0.7 mM to 100 mM KCl) indicate two salt-dependent conformational transitions. An abrupt transition occurs at about 7.5 mM ionic strength. Decreasing the ionic strength from 10 to 5 mM results in a decrease in s20,wof the ν1from 11.1 to 9.9 S. The diffusion coefficient D20,wdecreases from 3.3 to 2.7 × 10-7cm2sec-1. The ν1crosslinked with formaldehyde at 10 mM ionic strength do not undergo a similar salt-dependent change in s20,w. Another transition is observed at about 1 mM ionic strength; s20,wdecreases to 9.4 S and D20,wdecreases to 2.2 × 10-7cm2sec-1. Throughout the entire salt range the molecular weight of the ν1remains reasonably constant, implying that salt-dependent changes in the frictional coefficient are being observed. Various hydrodynamic models are considered as possible interpretations of the observed changes in the frictional coefficient. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0027-8424 1091-6490 |
DOI: | 10.1073/pnas.75.2.660 |