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We are deeply saddened by the passing of Amos Bairoch (1957–2025), the creator of PROSITE. We wish to dedicate our latest paper, published shortly before his death, to him. He will always be a source of inspiration to us.
Our deepest condolences go out to his family and friends, and to all those who had the privilege of working with him. Rest in peace, Amos. Your work will live on long after you are gone.
Amos Bairoch

PROSITE documentation PDOC51297
K-box domain profile


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PURL: https://purl.expasy.org/prosite/documentation/PDOC51297

Description

MADS genes in plants encode key developmental regulators of vegetative and reproductive development. The majority of the plant MADS proteins share a stereotypical MIKC structure. It comprises (from N- to C-terminal) an N-terminal domain, which is, however, present only in a minority of proteins; a MADS domain (see <PDOC00302>), which is the major determinant of DNA-binding but which also performs dimerization and accessory factor binding functions; a weakly conserved intervening (I) domain, which constitutes a key molecular determinant for the selective formation of DNA-binding dimers; a keratin-like (K-box) domain, which promotes protein dimerization; and a C-terminal (C) domain, which is involved in transcriptional activation or in the formation of ternary or quaternary protein complexes. The 80-amino acid K-box domain was originally identified as a region with low but significant similarity to a region of keratin, which is part of the coiled-coil sequence constituting the central rod-shaped domain of keratin [1,2,3].

The K-box protein-protein interaction domain which mediates heterodimerization of MIKC-type MADS proteins contains several heptad repeats in which the first and the fourth positions are occupied by hydrophobic amino acids suggesting that the K-box domain forms three amphipathic α-helices referred to as K1, K2, and K3 [3].

The profile we developed covers the entire K-box domain.

Last update:

February 2007 / First entry.

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Technical section

PROSITE method (with tools and information) covered by this documentation:

K_BOX, PS51297; K-box domain profile  (MATRIX)


References

1AuthorsAlvarez-Buylla E.R. Pelaz S. Liljegren S.J. Gold S.E. Burgeff C. Ditta G.S. Ribas de Pouplana L. Martinez-Castilla L. Yanofsky M.F.
TitleAn ancestral MADS-box gene duplication occurred before the divergence of plants and animals.
SourceProc. Natl. Acad. Sci. U.S.A. 97:5328-5333(2000).
PubMed ID10805792

2AuthorsHenschel K. Kofuji R. Hasebe M. Saedler H. Muenster T. Theissen G.
TitleTwo ancient classes of MIKC-type MADS-box genes are present in the moss Physcomitrella patens.
SourceMol. Biol. Evol. 19:801-814(2002).
PubMed ID12032236

3AuthorsYang Y. Fanning L. Jack T.
TitleThe K domain mediates heterodimerization of the Arabidopsis floral organ identity proteins, APETALA3 and PISTILLATA.
SourcePlant J. 33:47-59(2003).
PubMed ID12943540



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