This is a DNA-binding fold domain found in Phenylalanyl-tRNA Synthetase (EC:6.1.1.20) N-terminal region. This domain belongs to a superfamily of 'winged helix' DNA-biding domains. The topology of DBD-1 and DBD-3 closely resembles the topology of the Z-DNA-binding domain Zalpha of double-stranded RNA (dsRNA) adenosine deaminase and other domains from DNA-binding proteins. Mutational analysis indicate that DBD-1, 2 and 3 play critical roles in tRNA-Phe binding and recognition, i.e., from the drastic reduction of aminoacylation activity seen upon removal of the N-terminal domains [1].

1: Structure of human cytosolic phenylalanyl-tRNA synthetase: evidence for kingdom-specific design of the active sites and tRNA binding patterns. Finarov I, Moor N, Kessler N, Klipcan L, Safro MG; Structure. 2010;18:343-353. PMID:20223217