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Structural alteration from non-B to B-form could reflect DNase I hypersensitivity

Ramesh, N and Brahmachari, SK (1989) Structural alteration from non-B to B-form could reflect DNase I hypersensitivity. In: Journal of Biomolecular Structure & Dynamics, 6 (5). pp. 899-906.

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Official URL: http://www.ncbi.nlm.nih.gov/pubmed/2590508


Preferential cleavage of active genes by DNase I has been correlated with a structurally altered conformation of DNA at the hypersensitive site in chromatin. To have a better understanding of the structural requirements for gene activation as probed by DNase I action, digestability by DNase I of synthetic polynucleotides having the ability to adopt B and non-B conformation (like Z-form) was studied which indicated a marked higher digestability of the B-form of DNA. Left handed Z form present within a natural sequence in supercoiled plasmid also showed marked resistance towards DNase I digestion. We show that alternating purine-pyrimidine sequences adopting Z-conformation exhibit DNAse I foot printing even in a protein free system. The logical deductions from the results indicate that 1) altered structure like Z-DNA is not a favourable substrate for DNase I, 2) both the ends of the alternating purine-pyrimidine insert showed hypersensitivity, 3) B-form with a minor groove of 12-13 A is a more favourable substrate for DNase I than an altered structure, 4) any structure of DNA deviating largely from B form with a capacity to flip over to the B-form are potential targets for the DNase I enzymic probes in naked DNA.

Item Type: Journal Article
Publication: Journal of Biomolecular Structure & Dynamics
Publisher: Adenine Press
Additional Information: Copyright of this article belongs to Adenine Press.
Department/Centre: Division of Biological Sciences > Molecular Biophysics Unit
Date Deposited: 25 Aug 2010 09:30
Last Modified: 25 Aug 2010 09:30
URI: http://eprints.iisc.ac.in/id/eprint/31522

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