PlantTFDB
Plant Transcription Factor Database
v4.0
Previous version: v1.0, v2.0, v3.0
Phalaenopsis equestris
HD-ZIP Family
Species TF ID Description
PEQU_09386HD-ZIP family protein
PEQU_03172HD-ZIP family protein
PEQU_09578HD-ZIP family protein
PEQU_10044HD-ZIP family protein
PEQU_22440HD-ZIP family protein
PEQU_33250HD-ZIP family protein
PEQU_11247HD-ZIP family protein
PEQU_38453HD-ZIP family protein
PEQU_18501HD-ZIP family protein
PEQU_21815HD-ZIP family protein
PEQU_02596HD-ZIP family protein
PEQU_19567HD-ZIP family protein
PEQU_07102HD-ZIP family protein
PEQU_08358HD-ZIP family protein
PEQU_24587HD-ZIP family protein
PEQU_25207HD-ZIP family protein
PEQU_19348HD-ZIP family protein
PEQU_05681HD-ZIP family protein
PEQU_06648HD-ZIP family protein
PEQU_40453HD-ZIP family protein
PEQU_30359HD-ZIP family protein
PEQU_15186HD-ZIP family protein
PEQU_06107HD-ZIP family protein
PEQU_07232HD-ZIP family protein
PEQU_11690HD-ZIP family protein
PEQU_31999HD-ZIP family protein
PEQU_00587HD-ZIP family protein
PEQU_16338HD-ZIP family protein
PEQU_15387HD-ZIP family protein
PEQU_01516HD-ZIP family protein
PEQU_07490HD-ZIP family protein
PEQU_23277HD-ZIP family protein
PEQU_02925HD-ZIP family protein
PEQU_15890HD-ZIP family protein
PEQU_20351HD-ZIP family protein
HD-ZIP Family Introduction

A homeobox (HB) encodes a protein domain, the homeodomain (HD), which is a conserved 60-amino acid motif present in transcription factors found in all the eukaryotic organisms. This 60-amino acid sequence folds into a characteristic three-helix structure that is able to interact specifically with DNA. Most HDs are able to bind DNA as monomers with high affinity, through interactions made by helix III (the so-called recognition helix) and a disordered N-terminal arm located beyond helix I. The high degree of conservation of this type of domain among diverse proteins from different kingdoms indicates that this structure is crucial to maintain the HD functionality and that the role played by this domain is vital.

Members of the HD-Zip family have a leucine zipper motif (LZ) immediately downstream of the HD. The two motifs are present in transcription factors found in species belonging to other eukaryotic kingdoms, but their association in a single protein is unique to plants. The HD is responsible for the specific binding to DNA, whereas LZ acts as a dimerization motif. HD-Zip proteins bind to DNA as dimers, and the absence of LZ absolutely abolishes their binding ability, which indicates that the relative orientation of the monomers, driven by this motif, is crucial for an efficient recognition of DNA.

Ariel FD, Manavella PA, Dezar CA, Chan RL.
The true story of the HD-Zip family.
Trends Plant Sci, 2007. 12(9): p. 419-26.
PMID: 17698401