The SPR sensor detecting cytosine[bond]cytosine mismatches.
We have synthesized the first surface plasmon resonance (SPR) sensor that detects cytosine-cytosine (C[bond]C) mismatches in duplex DNA by immobilizing aminonaphthyridine dimer on the gold surface. The ligand consisting of two 2-aminonaphthyridine chromophores and an alkyl linker connecting them strongly stabilized the C[bond]C mismatches regardless of the flanking sequences. The fully matched duplexes were not stabilized at all under the same conditions. The C[bond]T, C[bond]A, and T[bond]T mismatches were also stabilized with a reduced efficiency. SPR analyses of mismatch-containing 27-mer duplexes were performed with the sensor surface on which the aminonaphthyridine dimer was immobilized. The response for the C[bond]C mismatch in 5'-GCC-3'/3'-CCG-5' was about 83 times stronger than that obtained for the fully matched duplex. The sensor successfully detects the C[bond]C mismatch at the concentration of 10 nM. SPR responses are proportional to the concentration of the C[bond]C mismatch in a range up to 200 nM. Aminonaphthyridine dimer could bind strongly to the C[bond]C mismatches having 10 possible flanking sequences with association constants in the order of 10(6) M(-1). The facile protonation of 2-aminonaphthyridine chromophore at pH 7 producing the hydrogen-bonding surface complementary to that of cytosine was most likely due to the remarkably high selectivity of 1 to the C[bond]C mismatch.
Kobori
Akio
A
PRESTO, Japan Science and Technology Agency (JST), Kyoto 615-8510, Japan.
Horie
Souta
S
Suda
Hitoshi
H
Saito
Isao
I
Nakatani
Kazuhiko
K
D020137:Base Pair Mismatch; D015374:Biosensing Techniques / Q000379:methods; D003596:Cytosine / Q000032:analysis* / Q000378:metabolism; D004247:DNA / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D009287:Naphthyridines / Q000138:chemical synthesis / Q000737:chemistry*; D020349:Surface Plasmon Resonance / Q000379:methods*
D009287:Naphthyridines; D003596:Cytosine; D004247:DNA