omp T: Escherichia coli K-12 structural gene for protein a (3b)

Chromosomal DNA from strain UT400, a previously described deletion mutant of Escherichia coli K-12 that lacks outer membrane protein a, failed to hybridize with plasmid DNA (pGGC110) containing the structural gene for protein a. We designate the genetic locus for protein a, located at approximately 12.5 min of the E. coli chromosome, ompT.