Binds to the 50S ribosomal subunit and prevents its association with the 30S ribosomal subunit to form the 70S initiation complex. Inhibits translation of both leadered and leaderless mRNAs, maybe by binding to the 50S ribosome subunit, preventing it from binding to the 30S subunit. Associates with the 50S ribosomal subunit, specifically with protein L14. Binds to 23S rRNA, possibly between where the 30S and 50S subunits associate to initiate translation. Constitutively expressed, further induced by cold (60) or heat (90 degrees Celsius) shock (at protein level). Modified in an unknown fashion (not phosphorylation) following release from 50S ribosomal subunits. Belongs to the eIF-6 family.