Journal article
Mutational analysis of the activator of late transcription, Alt , in the lactococcal bacteriophage TP901-1
An activator protein, Alt, synthesized during the early state of lytic infection is required for transcription of the late operon in the lactococcal phage TP901-1. In order to identify amino acid residues in the Alt protein required for activation of the TP901-1 late promoter, Plate, hydroxylamine mutagenesis was performed, resulting in almost saturating mutagenesis of alt.
Twenty-three different non-functional alt alleles containing one, and in one case two amino acid exchanges were isolated and analyzed. Eight of the twenty-three mutant proteins were still able to activate the Plate promoter to some extent. Our results show that alt encodes a protein of 16.7 kDa and that the last fourteen amino acids in the C-terminal part of the protein are required for activation of the Plate promoter.
By combining sequence analysis with experimental data we suggest that the C-terminal half of the Alt protein contains a helix-turn-helix-like motif involved in DNA binding. We also propose that the C-terminal half of the Alt protein may be involved in interactions with the bacterial RNA polymerase, whereas the N-terminal half of the protein is proposed to be important for the overall protein structure.
Language: | English |
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Publisher: | Springer-Verlag |
Year: | 2007 |
Pages: | 305-320 |
Journal subtitle: | Official Journal of the Virology Division of the International Union of Microbiological Societies |
ISSN: | 14328798 and 03048608 |
Types: | Journal article |
DOI: | 10.1007/s00705-006-0851-7 |
Alleles Amino Acid Sequence Amino Acid Substitution Biomedicine DNA Mutational Analysis Genes, Viral Helix-Turn-Helix Motifs Identify Amino Acid Residue Infectious Diseases Lactococcal Bacteriophage Lactococcus lactis Late Promoter Late Transcription Medical Microbiology Molecular Sequence Data Promoter Regions, Genetic Strain MP172 Transcription, Genetic Transcriptional Activation Viral Proteins Virology