DNA binding and intercalation by novel porphyrins: role of charge and substituents probed by DNase I footprinting and topoisomerase I unwinding

FEBS Letters

Austin, Caroline A.²  Kuroda, Reiko¹  Fisher, L.Mark²  Takahashi, Eitaro¹ 

[1] Department of Chemistry, College of Arts and Sciences, University of Tokyo (Komaba, Japan;Molecular Genetics Group, Department of Cellular and Molecular Sciences, St George's Hospital Medical School, University of London, London, UK

关键词: Porphyrin;    DNase I footprinting;    DNA unwinding;    Helix stabilization;    DNA intercalation;   

DOI  :  10.1016/0014-5793(90)80213-3

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Porphyrins carrying four charged sidechains, e.g., meso-tetrakis[4-N-methylpyridiniumyl]- and meso-tetrakis[4-N-(2-hydroxyethyl)pyridiniumyl]-porphyrin, bound and intercalated similarly into DNA as measured by helix stabilization and DNA unwinding studies in the presence of DNA topoisomerase I. Despite their different bulky sidechains, these complexes gave essentially identical DNase I footprinting patterns. In contrast, tetrasubstituted porphyrins carrying three phenyl rings and a single positively charged pyridiniumyl sidechain did not intercalate and exhibited little affinity for DNA. Thus, the presence of charged sidechains on the porphyrin rather than their identity appears to be critical for efficient DNA intercalation. The results are discussed in regard to current models for the porphyrin-DNA intercalation complex.

【 授权许可】

Unknown