Ontology Term : Pfam:PF01698 Floricaula / Leafy protein SAM domain EMBL-EBI

Description

This family consists of various plant development proteins which are homologues of floricaula (FLO) and Leafy (LFY) proteins which are floral meristem identity proteins. Mutations in the sequences of these proteins affect flower and leaf development. LFY proteins have been shown to binds semi-palindromic 19-bp DNA elements through its highly conserved C-terminal DBD. In addition to its well-characterized DBD, LFY possesses a second conserved domain at its amino terminus (LFY-N). This entry represents the SAM domain found in N -terminal of LFY proteins in plants. Crystallographic structure determination of LFY-N shows that LFY-N is a Sterile Alpha Motif (SAM) domain that mediates LFY oligomerization. It allows LFY to bind to regions lacking high-affinity LFYbs (LFY-binding sites) and confers on LFY the ability to access closed chromatin regions. Experiments carried out in plants, revealed that altering the capacity of LFY to oligomerize compromised its floral function and drastically reduced its genome-wide DNA binding. SAM oligomerization has been suggested to have a profound effect on a TF binding landscape by promoting cooperative binding of LFY to DNA, as was proposed for other oligomeric TFs, and it gives LFY access to closed chromatin regions that are notably refractory to TF binding. It has also been suggested that the biochemical properties of the SAM domain are evolutionary conserved in all plant species [3].

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