The MafG protein is a basic region-leucine zipper (bZip) Transcription Factor which binds via the major groove to the unusually long Maf Recognition Element (MARE) which is 13-14bp long. Although the 7-8bp core sequence of MARE is very similar to other DNA recognition sites, the flanking GC regions are very unique and play a critical role in MafG DNA recognition. The MARE sequence is: 5’-TGC-(TRE or CRE)-GCA-3
(where TRE and CRE are core motifs shared with bZip proteins AP-1 and CREB respectively) The ability of Maf proteins to recognise this extended DNA motif is what sets them apart from other bZip proteins.
This is only facilitated due to a key amino acid change. Whilst all other bZip proteins have Alanine at position 64, the Maf protein family has Tyrosine. Interestingly, it has also been uncovered that there are a number of key invariant amino acids that directly recognise the extended GC regions; however, this is only possible within the presence of Tyr64. https://www.wwpdb.org/pdb?id=pdb_00003a5t
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