Kinetic and Mutational Dissection of the Two ATPase Activities of Terminase, the DNA Packaging Enzyme of Bacteriophage λ†

Biochemistry ◽  
1996 ◽  
Vol 35 (8) ◽  
pp. 2796-2803 ◽  
Author(s):  
Young Hwang ◽  
Carlos E. Catalano ◽  
Michael Feiss
Keyword(s):  
Dna Packaging ◽  
Bacteriophage Λ ◽  
Dna Packaging Enzyme

scholarly journals THE INTERACTION OF cos WITH CHI IS SEPARABLE FROM DNA PACKAGING IN recA-recBC-MEDIATED RECOMBINATION OF BACTERIOPHAGE LAMBDA

Genetics ◽  
1983 ◽  
Vol 104 (4) ◽  
pp. 549-570
Author(s):  
Ichizo Kobayashi ◽  
Mary M Stahl ◽  
David Leach ◽  
Franklin W Stahl
Keyword(s):  
Escherichia Coli ◽  
Bacteriophage Lambda ◽  
Dna Packaging ◽  
Bacteriophage Λ ◽  
Entry Site ◽  
Two Component ◽  
General Recombination

ABSTRACT Chi (5′-GCTGGTGG) is a recombinator in RecA- RecBC-mediated recombination in Escherichia coli. In bacteriophage λ vegetative recombination, Chi is fully active only when it is correctly oriented with respect to cos, the site that defines the ends of the packaged chromosome. Here we demonstrate that packaging from cos is not necessary for this cos-Chi interaction. Our evidence suggests that correctly oriented cos is an activator of Chi. cos, as an activator, is (1) dominant over cos  -, (2) active opposite an extensive heterology, (3) able to interact with Chi only when on the same (cis) chromosome, and (4) able to interact with Chi at distances as far as ≥ 20 kb. Thus, cos and Chi form a two-component recombinator system for general recombination. cos may serve as an asymmetric entry site for a recombination enzyme that recognizes Chi in an asymmetric way.

scholarly journals Alterations of the Portal Protein, gpB, of Bacteriophage λ Suppress Mutations in cosQ, the Site Required for Termination of DNA Packaging

Genetics ◽  
2002 ◽  
Vol 161 (1) ◽  
pp. 21-31 ◽  
Author(s):  
Douglas J Wieczorek ◽  
Lisa Didion ◽  
Michael Feiss
Keyword(s):  
Dna Packaging ◽  
Missense Mutations ◽  
Bacteriophage Λ ◽  
Portal Protein ◽  
Suppression Effects

Abstract The cosQ site of bacteriophage λ is required for DNA packaging termination. Previous studies have shown that cosQ mutations can be suppressed in three ways: by a local suppressor within cosQ, an increase in the length of the λ chromosome, and missense mutations affecting the prohead’s portal protein, gpB. In the present work, revertants of a set of lethal cosQ mutants were screened for suppressors. Seven new cosQ suppressors affected gene B, which encodes the portal protein of the prohead. All seven were allelenonspecific suppressors of cosQ mutations. Experiments with several phages having two cosQ suppressors showed that the suppression effects were additive. Furthermore, these double suppressors had minimal effects on the growth of cosQ+ phages. These trans-acting suppressors affecting the portal protein are proposed to allow the mutant cosQ site to be more efficiently recognized, due to the slowing of the rate of translocation.

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