Electrophoresis of DNA restriction fragments in poly-N-acryloyl-tris gels

Poly-N-acryloyl-tris(hydroxymethyl)aminomethane (NAT) gels were evaluated as a matrix for DNA electrophoresis. The resolution of DNA restriction fragments in three poly(NAT)-N,N'-methylenebisacrylamide (Bis) gels (4, 5, and 6%) was compared with the resolution in polyacrylamide (AA)-Bis gels of the same percentage. Poly(NAT) gels were found to give a substantially improved separation of DNA fragments larger than 200 bp. In contrast to poly(AA) gels, DNA fragments of up to 4 kbp were well resolved in the new matrix. By pulse-field electrophoresis the useful separation range of poly(NAT) gels was expanded to at least 23 kbp. For DNA fragments below 10 kbp, the resolution was better than that in a 0.7% agarose gel. Thus poly(NAT) gels are most suitable for the electrophoretic separation of DNA molecules whose size is out of the optimal fractionation range of poly(AA) or agarose gels.