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Infrared Spectroscopic Observation of a G–C + Hoogsteen Base Pair in the DNA:TATA‐Box Binding Protein Complex Under Solution Conditions
Author(s) -
Stelling Allison L.,
Liu Amy Y.,
Zeng Wenjie,
Salinas Raul,
Schumacher Maria A.,
AlHashimi Hashim M.
Publication year - 2019
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201902693
Subject(s) - chemistry , dna , base pair , molecular structure of nucleic acids: a structure for deoxyribose nucleic acid , crystallography , stereochemistry , biochemistry
Hoogsteen DNA base pairs (bps) are an alternative base pairing to canonical Watson–Crick bps and are thought to play important biochemical roles. Hoogsteen bps have been reported in a handful of X‐ray structures of protein–DNA complexes. However, there are several examples of Hoogsteen bps in crystal structures that form Watson–Crick bps when examined under solution conditions. Furthermore, Hoogsteen bps can sometimes be difficult to resolve in DNA:protein complexes by X‐ray crystallography due to ambiguous electron density and by solution‐state NMR spectroscopy due to size limitations. Here, using infrared spectroscopy, we report the first direct solution‐state observation of a Hoogsteen (G–C + ) bp in a DNA:protein complex under solution conditions with specific application to DNA‐bound TATA‐box binding protein. These results support a previous assignment of a G–C + Hoogsteen bp in the complex, and indicate that Hoogsteen bps do indeed exist under solution conditions in DNA:protein complexes.