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A Minimal Load‐and‐Lock Ru II Luminescent DNA Probe
Author(s) -
Newton Matthew D.,
Fairbanks Simon D.,
Thomas Jim A.,
Rueda David S.
Publication year - 2021
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.202108077
Subject(s) - dna , chemistry , dna supercoil , dna origami , luminescence , biophysics , optical tweezers , threading (protein sequence) , intercalation (chemistry) , force spectroscopy , molecule , duplex (building) , atomic force microscopy , dna ligase , crystallography , nanotechnology , materials science , dna replication , biochemistry , protein structure , biology , physics , optoelectronics , organic chemistry , quantum mechanics , inorganic chemistry
Abstract Threading intercalators bind DNA with high affinities. Here, we describe single‐molecule studies on a cell‐permeant luminescent dinuclear ruthenium(II) complex that has been previously shown to thread only into short, unstable duplex structures. Using optical tweezers and confocal microscopy, we show that this complex threads and locks into force‐extended duplex DNA in a two‐step mechanism. Detailed kinetic studies reveal that an individual stereoisomer of the complex exhibits the highest binding affinity reported for such a mono‐intercalator. This stereoisomer better preserves the biophysical properties of DNA than the widely used SYTOX Orange. Interestingly, threading into torsionally constrained DNA decreases dramatically, but is rescued on negatively supercoiled DNA. Given the “light‐switch” properties of this complex on binding DNA, it can be readily used as a long‐lived luminescent label for duplex or negatively supercoiled DNA through a unique “load‐and‐lock” protocol.