Oligonucleotide-minor groove binder conjugates and their complexes with complementary DNA: effect of conjugate structural factors on the thermal stability of duplexes.
Synthetic polycarboxamide minor groove binders (MGB) consisting of N-methylpyrrole (Py), N-methylimidazole (Im), N-methyl-3-hydroxypyrrole (Hp) and beta-alanine (beta) show strong and sequence-specific interaction with the DNA minor groove in side-by-side antiparallel or parallel orientation. Two MGB moieties covalently linked to the same terminal phosphate of one DNA strand stabilize DNA duplexes formed by this strand with a complementary one in a sequence-specific manner, similarly to the corresponding mono-conjugated hairpin structures. The series of conjugates with the general formula Oligo-(L-MGB-R)m was synthesized, where m = 1 or 2, L = linker, R = terminal charged or neutral group, MGB = -(Py)n-, -(Im)n- or -[(Py/Im)n-(CH2)3CONH-(Py/Im)n-] and I < n < 5. Using thermal denaturation, we studied effects of structural factors such as m and n, linker L length, nature and orientation of the MGB monomers, the group R and the backbone (DNA or RNA), etc. on the stability of the duplexes. Structural factors are more important for linear and hairpin monophosphoroamidates than for parallel bis-phosphoroamidates. No more than two oligocarboxamide strands can be inserted into the duplex minor groove. Attachment of the second sequence-specific parallel ligand [-L(Py)4R] to monophosphoroamidate conjugate CGTTTATT-L(Py)4R leads to the increase of the duplex Tm, whereas attachment of [-L(Im)4R] leads to its decrease. The mode of interaction between oligonucleotide duplex and attached ligands could be different (stacking with the terminal A:T pair of the duplex or its insertion into the minor groove) depending on the length and structure of the MGB.
Ryabinin
Vladimir A
VA
State Research Center of Virology and Biotechnology Vector, Kol'tsovo, Institute of Molecular Biology, Novosibirsk Region, Russia.
Boutorine
Alexandre S
AS
Hélène
Claude
C
Pyshnyi
Dmitrii V
DV
Sinyakov
Alexandre N
AN
D018076:DNA, Complementary / Q000737:chemistry*; D009693:Nucleic Acid Hybridization; D009841:Oligonucleotides / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism; D013696:Temperature
D018076:DNA, Complementary; D009841:Oligonucleotides