Professor Yves Mely
Biophotonics and Pharmacology laboratory, UMR 7213 CNRS
Université de Strasbourg,  ILLKIRCH, France

Monitoring Protein-Nucleic Acid Interactions with Environment-Sensitive Fluorescent Amino-Acid and Nucleotide Analogues

Due to their exquisite sensitivity, fluorescence-based techniques are ideally suited to obtain general information on the binding and dynamics of interacting biomolecules. However, they are more limited in providing site-selective information on a given amino-acid or nucleotide, due to the lack of appropriate tools.

To fill this gap, we developed original amino acid and nucleotide analogues based on 3-hydroxychromone (3HC) probes that show a two band emission highly sensitive to minute changes in their environment.  These analogues were used to characterize the interaction of the nucleocapsid protein NCp7, a key HIV-1 protein, with its nucleic acid targets. The 3HC-based amino acid was found to perfectly mimic the highly conserved Trp37 residue that plays a key role in NCp7 structure and activity. It was also shown to sensitively and site-selectively report on the nucleic acid chaperone mechanism of this protein and to help identify the molecular targets of NCp7 in the cellular context.

To complete this picture, we also monitored the interactions from the oligonucleotide point of view, using  a 3HC-based fluorescent nucleotide analogue that possesses the characteristics of a universal base and a thieno-deoxyguanosine (thG) residue, a nearly perfect fluorescent substituent of the guanine base, highly sensitive to protein binding and duplex formation. 

This work was supported by ANR (07-BLAN-0287), FRM (DCM20111223038), ANRS and the European Project THINPAD (FP7 – Grant Agreement 601969).

Host: Associate professor Victoria Birkedal, Interdisciplinary Nanoscience Center, Aarhus University