DEAD Box - DEAD Box Family

DEAD Box Family

DEAD box proteins were first brought to attention in the late 1980s in a study that looked at a group of NTPases that were similar in sequence to the eIF4A RNA helicase sequence. The results of this study showed that these proteins (p68,SrmB, MSS116, vasa, PL10, mammalian eIF4A, yeast eIF4A) involved in RNA metabolism had several common elements. There were nine common sequences found to be conserved amongst the studied species, which is an important criterion of the DEAD box family. The nine conserved motifs are as follows, Q-motif, motif 1, motif 1a, motif 1b, motif II, motif III, motif IV, motif V, and motif VI, as shown in the figure. Motif II is also known as the Walker B motif and contains the amino acid sequence D-E-A-D (asp-glu-ala-asp), which gave this family of proteins the name “DEAD box”. Motif 1, motif II, the Q motif, and motif VI are all needed for ATP binding and hydrolysis, while motifs, 1a, 1b, III, IV, and V may be involved in intramolecular rearrangements and RNA interaction.