Component of antiviral defense system Zorya type I, composed of ZorA, ZorB, ZorC and ZorD. Expression of Zorya type I in E.coli (strain MG1655) confers 10,000-fold resistance to phage SECphi27, 100-fold resistance to lambda, and 10-fold resistance to T7. While most T7 infected Zorya-containing cells undergo abortive infection, a minority produce viable phage progeny. These eventually accumulate to a high multiplicity of infection, leading to culture collapse by 2 hours after initial infection (PubMed:29371424). ZorA and ZorB probably assemble in the cell inner membrane and exert their effect there. This may have ATPase activity (Probable). When this gene is missing the Zorya system does not confer resistance to SECphi27 in E.coli.