REORIENTATION OF LARGE DNA-MOLECULES IN CONCENTRATED POLYACRYLAMIDE SOLUTION DURING CROSSED-FIELD ELECTROPHORESIS

Recently, we found that, in concentrated neutral solutions, DNA molecu les migrate in linear conformation under steady electric field. In thi s paper, we report the conformational change of DNA during 120 degrees crossed-field electrophoresis in the same polymer solution. We found that, in concentrated polyacrylamide solutions, the reorientation proc ess of DNAs becomes simple: the DNA goes back along the previous track and the reorientation time is longer for larger DNA. Such a backtrack motion has been thought to be an essential motion for the separation of DNA fragments in pulsed field gel electrophoresis. We expect that t his phenomenon is useful for a more efficient separation technique of large DNAs than the current pulsed field gel electrophoresis.