Protein eukaryotic homeodomains

Several DNA-binding motifs have been described, but here we focus on two that play prominent roles in the binding of DNA by regulatory proteins the helix-tum-helix and the zinc finger. We also consider a type of DNA-binding domain—the homeodomain—found in some eukaryotic proteins. 

Homeodomain Another type of DNA-binding domain has been identified in a number of proteins that function as transcriptional regulators, especially during eukaryotic... 

DNA-Binding Proteins that Regulate Transcription in Eukaryotes Are Often Asymmetrical The Homeodomain Zinc Finger Leucine Zipper Helix-Loop-Helix... 

The most striking difference between DNA-binding proteins in prokaryotes and eukaryotes has to do with the symmetry of the interaction. In prokaryotes the binding proteins almost always interact in a symmetrical fashion with the DNA. In eukaryotes most of the cases that have been examined so far involve proteins that interact in an asymmetrical fashion with the DNA. In many cases the regulatory proteins interact in multisubunit complexes that contain nonidentical subunits. Four different types of structural motifs are discussed The homeodomain, the zinc finger, the leucine zipper, and the helix-loop-helix. 

Homeodomain Proteins Many eukaryotic transcription factors that function during development contain a conserved 60-residue DNA-binding motif that is similar to the helix-turn-helix motif of bacterial repressors. Called homeodomain proteins, these transcription factors were first identified in Drosophila mutants in which one body part was transformed into another during development (Chapter 15). The conserved homeodomain sequence has also been found in vertebrate transcription factors, including those that have similar master control functions in human development. 

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