|PROSITE documentation PDOC51141 [for PROSITE entry PS51141]|
SQUAMOSA promoter binding proteins (SBPs) form a major family of plant-specific transcription factors related to flower development. They share a highly conserved DNA-binding domain that contains two zinc-binding sites. Among the 11 possible ligands for the zinc atoms that are conserved in the SBP zinc finger, only 8 are used. The SBP zinc finger follows the general pattern C-x4-C-x16-C-x2-[HC]-x15-C-x2-C-x3-H-x11-C. Three other histidines are well conserved but not involved in zinc binding [1,2].
In vitro experiments show that the SBP zinc finger preferentially binds the consensus sequence -TNCGTACAA- . However, little is known of the physiological functions of these putative transcriptional regulators beyond their ability to bind DNA.
The solution structure of the SBP zinc finger has been solved (see <PDB:1UL4>) . The first four Cys or His coordinate one zinc ion and the last four coordinate the other. It can be viewed as two structural subdomains, each subdomain containing a single zinc-binding pocket. The N-terminal subdomain consists of two short α helices whereas the C-terminal one contains a three-stranded antiparallel β-sheet.Last update:
July 2005 / First entry.
PROSITE method (with tools and information) covered by this documentation:
|1||Authors||Klein J. Saedler H. Huijser P.|
|Title||A new family of DNA binding proteins includes putative transcriptional regulators of the Antirrhinum majus floral meristem identity gene SQUAMOSA.|
|Source||Mol. Gen. Genet. 250:7-16(1996).|
|2||Authors||Yamasaki K. Kigawa T. Inoue M. Tateno M. Yamasaki T. Yabuki T. Aoki M. Seki E. Matsuda T. Nunokawa E. Ishizuka Y. Terada T. Shirouzu M. Osanai T. Tanaka A. Seki M. Shinozaki K. Yokoyama S.|
|Title||A novel zinc-binding motif revealed by solution structures of DNA-binding domains of Arabidopsis SBP-family transcription factors.|
|Source||J. Mol. Biol. 337:49-63(2004).|
|3||Authors||Cardon G. Hohmann S. Klein J. Nettesheim K. Saedler H. Huijser P.|
|Title||Molecular characterisation of the Arabidopsis SBP-box genes.|