DNA end degradation evasion by virus (kw:KW-1256)

Several types of bacteria including Escherichia coli or Salmonella typhimurium encode enzymes responsible for the degradation of free DNA ends. When functioning in their exonuclease mode, helicase/nuclease proteins such as bacterial RecBCD (also called exonuclease V) or AddAB degrade any free DNA ends as well as linear dsDNA products resulting from restriction Type II cleavage .


Any bacterial virus that exposes free DNA ends as part of its life cycle must find a means to evade destruction by these host nucleases. Bacterial viruses have elaborated different strategies to circumvent degradation of their free DNA ends. For example, bacteriophage T4 gene product 2 (gp2) is able to interact with viral DNA ends to prevent recognition of the RecBCD complex and subsequent cleavage of the DNA. Gam protein of bacteriophage lambda also inhibits the interaction between RecBCD and viral genome ends.

Matching UniProtKB/Swiss-Prot entries

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6 entries grouped by strain

2 entries

Escherichia phage Mu (Bacteriophage Mu) reference strain

CIRCN_BPMU DNA circularization protein N (64 kDa virion protein) (Gene product 43) (gp43) (Gene product N) ...
GAM_BPMU Putative DNA ends protecting protein gam (Gene product 10) (gp10)

1 entry

Enterobacteria phage T4 (Bacteriophage T4) reference strain

DNAPR_BPT4 Terminal DNA protecting protein (Gene product 64) (gp64) (Head protein Gp2)

1 entry

Escherichia phage lambda (Bacteriophage lambda) reference strain

GAM_LAMBD Host-nuclease inhibitor protein gam

1 entry

Mycobacterium phage Corndog (Mycobacteriophage Corndog) reference strain

KU_BPMCO Protein Ku (Cd-Ku) (Gp87)

1 entry

Mycobacterium phage Omega (Mycobacteriophage Omega) reference strain

KU_BPMOM Protein Ku (Gp206) (Omega-Ku)