ANALYSIS OF A MUTATION AFFECTING THE SPECIFICITY DOMAIN FOR PROHEAD BINDING OF THE BACTERIOPHAGE-LAMBDA TERMINASE

被引:38
作者
SIPPY, J
FEISS, M
机构
[1] Department of Microbiology, University of Iowa, Iowa City
关键词
D O I
10.1128/jb.174.3.850-856.1992
中图分类号
Q93 [微生物学];
学科分类号
071005 ; 100705 ;
摘要
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.
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页码:850 / 856
页数:7
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