An evolutionarily nonconserved region of ~250 amino-acids can be deleted from the amino-terminal part of the β subunit of Escherichia coli RNA polymerase without effect on the enzyme's basic function. The non-essential segment is located between two highly conserved motifs and is flanked by sequences participating in the rifampicin-binding site. The results define the second non-essential domain in the β subunit, in addition to the more distal dispensable segment identified previously. The Alc protein of bacteriophage T4 participates in the host transcription shutoff after infection by causing premature termination of transcription on E. coli DNA. Point mutations which prevent Alc action in vivo change amino acids in the non-essential NH2-terminal domain of the β subunit. These point mutations as well as deletions which remove the non-essential region also prevent Alc action. Thus, in the RNA polymerase molecule, the proximal non-essential domain of β may function as an acceptor of Alc or other regulatory factors.
|Original language||English (US)|
|Number of pages||6|
|Journal||Journal of Biological Chemistry|
|Publication status||Published - Jan 1 1994|
All Science Journal Classification (ASJC) codes
- Molecular Biology
- Cell Biology