Specific DNA-protein interactions on mica investigated by atomic force microscopy.
DNA processing by site-specific proteins on surface remains a challenging issue for nanobioscience applications and, in particular, for high-resolution imaging by atomic force microscopy (AFM). To obtain high-resolution conditions, mica, an atomically flat and negatively charged surface, is generally used. However, even though many specific DNA/protein interactions have already been observed by AFM, little is known about DNA accessibility to specific enzymes on mica. Here we measured the accessibility of adsorbed DNA to restriction endonucleases (EcoRI and EcoRV) using AFM. By increasing the concentration of divalent or multivalent salts, DNA adsorption on mica switches from weak to strong binding. Interestingly, while the accessibility of strongly bound DNA was inhibited, loosely adsorbed DNA was efficiently cleaved on mica. This result opens new perspective to study DNA/protein interaction by AFM or to modify specifically DNA on surface.
Pastré
David
D
Laboratoire Structure et Activité des Biomolécules Normales et Pathologiques, INSERM/UEVE U829, Université d'Evry val d'Essonne, Evry F-91025, France. david.pastre@univ-evry.fr
Hamon
Loïc
L
Sorel
Isabelle
I
Le Cam
Eric
E
Curmi
Patrick A
PA
Piétrement
Olivier
O
D000327:Adsorption; D000538:Aluminum Silicates / Q000737:chemistry; D004247:DNA / Q000737:chemistry*; D015246:Deoxyribonuclease EcoRI / Q000737:chemistry* / Q000378:metabolism; D015252:Deoxyribonucleases, Type II Site-Specific / Q000737:chemistry* / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology; D018625:Microscopy, Atomic Force; D013499:Surface Properties
D000538:Aluminum Silicates; D004247:DNA; D015246:Deoxyribonuclease EcoRI; D015252:Deoxyribonucleases, Type II Site-Specific; C027440:GATATC-specific type II deoxyribonucleases; C011934:mica