Putative HNH endonuclease component of antiviral defense system retron Vc95, composed of a non-coding RNA (ncRNA), a reverse transcriptase (RT), a probable ATP-binding protein and this protein. Expression of retron Vc95 confers protection against bacteriophages T2, T4 and T6. At multiplicity of infection (MOI) of 0.02 cultures slow growth when infected with T4 but do not collapse, at MOI 2 cultures enter growth stasis.