Double-strand DNA can be immobilizd on the plain beads. Because guanine bonds easily with epoxy groups, prepare double-strand DNA with 4 – 10 guanine bases projecting from the end. (If ligation will be performed, the same number of cytosine bases should protrude from the end of the complementary strand.) If the lengths of the bases are short, steric hindrance may prevent recovery of the target protein. Therefore as necessary use ligation reactions for joining and prepare approximately 500 base pairs. When this double-strand DNA is mixed with the plain beads, the projecting guanine bonds with the epoxy radicals on the bead surfaces to bind the DNA to the beads.
Single-strand DNA and RNA can be immobilizd on the plain beads, too. Because
DNA and RNA are immobilized by various parts on beads when DNA and RNA
are immobilized as single-strand, after having immobilized DNA with double-strand,
it dissociates to single strand. In the case of RNA, it is immobilized
like immobilization metod of double-strand DNA by forming a hybrid of RNA
introduced 4-10 bases guanine and complementary DNA.
It is possible to introduce a functional groups onto the ends of DNA or RNA strands and bind the DNA or RNA to FG beads® via these functional groups. DNA or RNA with introduced NH2 group can be immobilized on NHS beads. DNA or RNA with introduced SH groups can be immobilized on beads where N-alkylmaleimide groups or iodoacetamide groups have been introduced onto the surfaces. Biotin-modified DNA or RNA can be immobilized on streptavidin beads. Streptavidin beads do not react with DNA and RNA bases, and bond selectively with the biotin-modified strand ends.