Open AccessAnalysis of a mutation affecting the specificity domain for prohead binding of the bacteriophage lambda terminase
Author(s) -
Jean Sippy,
Michael Feiss
Publication year - 1992
Publication title -
journal of bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.652
H-Index - 246
eISSN - 1067-8832
pISSN - 0021-9193
DOI - 10.1128/jb.174.3.850-856.1992
Subject(s) - biology , siphoviridae , bacteriophage , lambda phage , microbiology and biotechnology , protein subunit , mutation , amino acid , concatemer , capsid , genetics , gene , escherichia coli , genome
Genetic studies have identified a specificity domain for prohead binding in the C-terminal 32 amino acids of gpA, the large subunit of bacteriophage lambda terminase (S. Frackman, D. A. Siegele, and M. Feiss, J. Mol. Biol. 180:283-300, 1984). In the present work, an amber mutation, Aam42, in the fifth-to-last codon of the A gene was found to be lethal in nonsuppressing hosts. The mutation, expected to generate gpA lacking the last five amino acids, caused the production of a terminase that cut cos efficiently both in vivo and in vitro but was defective in DNA packaging. lambda Aam42 lysates contained unused proheads, consistent with a defect in prohead binding. Aam42 terminase was more strongly dependent than wild-type terminase on gpFI, the catalyst of prohead binding. Like wild-type terminase, Aam42 terminase did not cut cos in vivo when prohead assembly was blocked by a mutation in one of the genes encoding the prohead.