English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The chemical structure and conformation of the new antitumor antibiotic saframycin R have been determined by high field 1H and 13C NMR as well as FAB mass spectrometry. Unlike other members of the saframycin family, saframycin R contains a reduced quinone ring bearing a glycolic ester moiety. Saframycin R exhibits acid promoted equilibrium and reversible covalent binding to DNA templates and, in the presence of a reducing agent, oxygen dependent single strand scission of supercoiled DNA. The extent of DNA scission is enhanced by in situ porcine carboxyl esterase or base catalyzed cleavage of the glycolic ester function plausibly by the release of the more reactive reduced saframycin A. This suggests that saframycin R may be regarded as a less toxic pro-drug for the active forms of saframycins A or S.

Structure and conformation of saframycin R determined by high field 1H and 13C NMR and its interactions with DNA in solution.