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Chemically Induced Hairpin Formation in DNA Monolayers. Emily A. Smith, Motoki Kyo, Hiroyuki Kumasawa, Kazuhiko Nakatani, Isao Saito, and Robert M. Corn* J. Am. Chem. Soc., 124 (24), 6810 -6811(2002). MEC Seminar 10/18/02 Summarized by Park, Ji-Yoon. Abstract.
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Chemically Induced Hairpin Formation in DNA Monolayers Emily A. Smith,Motoki Kyo,Hiroyuki Kumasawa,Kazuhiko Nakatani,Isao Saito, and Robert M. Corn*J. Am. Chem. Soc., 124 (24),6810 -6811(2002) MEC Seminar 10/18/02 Summarized by Park, Ji-Yoon
Abstract • A naphthyridine dimer binds specifically to G-G mismatches • Induce hairpin formation in oligonucleotides immobilized onto chemically modified gold surfaces • SPR imaging measurements • Binding of the naphthyridine dimer to G-G mismatches within the stem portion of an immobilized 42-mer oligonucleotide
Previous Study by Robert M.Corn • Surface Plasmon Resonance Imaging Measurements of DNA and RNA Hybridization Adsorption onto DNA Microarrays - Anal. Chem. 73 (1), 1 -7(2001) • Surface plasmon resonance imaging measurements of ultrathin organic films - Annu. Rev. Phys. Chem. 51, 41-63(2000) • The procedure used for constructing DNA microarrays on gold surfaces has been previously reported - J. Am. Chem. Soc. 121, 8044-8051(1999)
Structure of the G-G Mismatch Scheme 1. Structure of the G-G Mismatch Stabilizing Naphthyridine Dimer
Molecular Design of a Ligand(1-4)Nature Biotechnology 19, 51 - 55 (2001) (A) Structures of naphthyridine dimers1 and 2 (green), and hydrogen-bonding pattern to guanine (red)(B) An illustration of duplex containing a G-G mismatch (C) Hypothetical structure of the G-G mismatch regarded as two consecutive guanine bulges (D) Aproposed binding model for ligand 1 to the G-G mismatch(E) Molecular models of the simulated complex of ligand 1 and DNA containing the G-G mismatch viewed from the major groove side (left) and the minor groove side (right)
SPR Assay by a Sensor Chip(2)Nature Biotechnology 19, 51 - 55 (2001) (A) The angle for a reflection of a polarized light would be changed as a binding of DNAs to the sensor surface. (B) The change of the angle is computed to the change of response unit (RU) and plotted against time.
SPR difference image of a four-component DNA array (a) Surface-bound 11-mer DNA sequence(b) SPR imaging measurement - Each immobilized oligonucleotide differs by one base - The image condition; 250 M naphthyridine dimer with 1 uM DNA complement - Perfect match & the G-G mismatch Fig 1. SPR difference image of a four-complement DNA array
How “Chemically induced” Hairpins • Surface-bound DNA sequence (X , Y; 18 mers) • Complementary to the sequence of an 18-mer probe (Z) • Flanking regions - act as the stem of a hairpin • Sequence “ Y” forms a hairpin structure in the presence of Naphthyridine dimer Scheme 2. Schematic representation of the oligonucleotides used in Fig 2
SPR difference images of a two-component DNA array (a) In the absence of the dimer - hybridization adsorption is observed to both X and Y - no hairpin formation in sequence Y (b) Exposure to the naphthyridine dimer- Increase in reflectivity only for sequence Y - Hairpin formation (c) After the subsequent exposure of the surface to the complement molecule Z- hybridization adsorption is only observed to the sequence X element Fig 2. SPR difference images of a two-component DNA array obtained from the SPR image before and after