DNA Binding Made Easy

A mechanism by which proteins of bacterial plant pathogens recognize and control the expression of host plant genes to promote infection is identified. All cells encode specific DNA binding proteins that ensure that genetic material is appropriately expressed, replicated, and transmitted from one generation to the next. Mother Nature solved the DNA recognition problem by inventing a handful of protein motifs, including the zinc finger, the helix-turn-helix, and the leucine zipper. As is the case with all good solutions to a problem, these motifs are used over and over again in biological systems; for example, DNA binding proteins containing the helix-turn-helix motif are found in both prokaryotes and eukaryotes, and zinc finger—containing proteins are the most abundant protein class encoded by the human genome. It is surprising, therefore, to learn from studies by Boch et al. (1) on page 1509 and Moscou and Bogdanove (2) on page 1501 of this issue, about a new DNA binding motif that has heretofore escaped description.