Length and Location of the Dipeptide Permease in E. coli
The gene dpp codes for the dipeptide permease, a transport system in E. coli about which little is known. An attempt was made to determine the length and location of dpp and its protein products in several isolates of the bacterium in order to determine its mechanism of action. A mini-TnlO, which is a transposon, was inserted within the DNA in dpp. The location of a mini-TnlO was found in the 1.7 kb fragment in isolate 1105 and helps determine the extent of dpp. The other isolates, 1108, 1107, and 1114 gave no clear indication where the mini-TnlO was located. A survival curve of S159 (/I ind-) helped elucidate the dpp protein products by showing which U.V. dose stopped bacterial protein synthesis while allowing substantial phage-encoded protein synthesis.