An NMR Spectroscopy Study on the Exchangeable Protons and Hydrogen Bonds in Tetracycline Hydrochloride

Abstract

Tetracyclines are a class of broad-spectrum antibiotics that have antibacterial activities against Gram-positive and Gram-negative bacteria, including Mycoplasma, Chlamydia, and Rickettsia. In this paper, we report the one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR) studies on the exchangeable protons and hydrogen bound in tetracycline hydrochloride (TC). The NMR results were compared with the results obtained from the crystal structures of free tetracycline and RNA- and protein-bound complexes. The H-bonding frameworks in the drug and their correlation with drug activity were discussed. The1H and 13C NMR signals of TC and its derivatives were fully assigned and interpreted, and the misassigned signals in previous reports were corrected. The results of this study could be conducive to further exploration of the structure-function correlation of this drug family in more complex biological and environmental systems.

Keywords

• nmr
• tetracycline
• exchangeable protons
• hydrogen bond