Summary: Kelch motif
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Kelch motif Edit Wikipedia article
|Structure of Galactose oxidase containing kelch repeats.|
|Galactose oxidase, central domain|
|Galactose oxidase, central domain|
The Kelch motif is a region of protein sequence found widely in proteins from bacteria and eukaryotes. The motif is named after the Drosophila mutant in which it was first identified. This sequence motif is composed of about 50 amino acid residues which form a structure of a four stranded beta-sheet "blade". This sequence motif is found in between six and eight copies per protein which fold together to form a larger circular solenoid structure called a beta-propeller domain.
 Proteins containing Kelch motifs
The Kelch motif is widely found in eukaryotic and bacterial species. Notably the human genome contains around 100 proteins containing the Kelch motif. Within individual proteins the motif occurs multiple times. For example, the motif appears 6 times in Drosophila egg-chamber regulatory protein. The motif is also found in mouse protein MIPP and in a number of poxviruses. In addition, kelch repeats have been recognised in alpha- and beta-scruin, and in galactose oxidase from the fungus Dactylium dendroides.
The structure of galactose oxidase reveals that the repeated Kelch sequence motif corresponds to a 4-stranded anti-parallel beta-sheet motif that forms the repeat unit in a super-barrel structural fold commonly known as a beta propeller.
The known functions of kelch-containing proteins are diverse:
- scruin is an actin cross-linking protein;
- galactose oxidase catalyses the oxidation of the hydroxyl group at the C6 position in D-galactose;
- neuraminidase hydrolyses sialic acid residues from glycoproteins;
- kelch may have a cytoskeletal function, as it is localised to the actin-rich ring canals that connect the 15 nurse cells to the developing oocyte in Drosophila.
 See also
- Ito N, Phillips SE, Stevens C, et al. (March 1991). "Novel thioether bond revealed by a 1.7 A crystal structure of galactose oxidase". Nature 350 (6313): 87–90. doi:10.1038/350087a0. PMID 2002850.
- Adams J, Kelso R, Cooley L (January 2000). "The kelch repeat superfamily of proteins: propellers of cell function". Trends Cell Biol. 10 (1): 17–24. doi:10.1016/S0962-8924(99)01673-6. PMID 10603472.
- Xue F, Cooley L (1993). "kelch encodes a component of intercellular bridges in Drosophila egg chambers". Cell 72 (5): 681–693. doi:10.1016/0092-8674(93)90397-9. PMID 8453663.
- Way M, Sanders M, Matsudaira P, Chafel M, Knight A, Tu YH (1995). "beta-Scruin, a homologue of the actin crosslinking protein scruin, is localized to the acrosomal vesicle of Limulus sperm". J. Cell Sci. 108: 3155–3162. PMID 7593276.
- Way M, Sakai J, Sanders M, Garcia C, Matsudaira P (1995). "Sequence and domain organization of scruin, an actin-cross-linking protein in the acrosomal process of Limulus sperm". J. Cell Biol. 128 (1): 51–60. doi:10.1083/jcb.128.1.51. PMC 2120335. PMID 7822422. //www.ncbi.nlm.nih.gov/pmc/articles/PMC2120335/.
- Doolittle RF, Bork P (1994). "Drosophila kelch motif is derived from a common enzyme fold". J. Mol. Biol. 236 (5): 1277–1282. doi:10.1016/0022-2836(94)90056-6. PMID 8126718.
- Keen JN, Ito N, Phillips SE, Stevens C, Ogel ZB, McPherson MJ, Yadav KD, Knowles PF (1991). "Novel thioether bond revealed by a 1.7 A crystal structure of galactose oxidase". Nature 350 (6313): 87–90. doi:10.1038/350087a0. PMID 2002850.
- Ito N, Phillips SE, Yadav KD, Knowles PF (1994). "Crystal structure of a free radical enzyme, galactose oxidase". J. Mol. Biol. 238 (5): 794–814. PMID 8182749.
Kelch motif Provide feedback
The kelch motif was initially discovered in Kelch (Q04652). In this protein there are six copies of the motif. It has been shown that Q04652 is related to Galactose Oxidase  for which a structure has been solved . The kelch motif forms a beta sheet. Several of these sheets associate to form a beta propeller structure as found in PF00064 PF00400 and PF00415.
Ito N, Phillips SE, Stevens C, Ogel ZB, McPherson MJ, Keen JN, Yadav KD, Knowles PF; , Nature 1991;350:87-90.: Novel thioether bond revealed by a 1.7 A crystal structure of galactose oxidase. PUBMED:2002850 EPMC:2002850
External database links
This tab holds annotation information from the InterPro database.
InterPro entry IPR011498
Kelch is a 50-residue motif, named after the Drosophila mutant in which it was first identified [PUBMED:8453663]. This sequence motif represents one beta-sheet blade, and several of these repeats can associate to form a beta-propeller. For instance, the motif appears 6 times in Drosophila egg-chamber regulatory protein, creating a 6-bladed beta-propeller. The motif is also found in mouse protein MIPP [PUBMED:8453663] and in a number of poxviruses. In addition, kelch repeats have been recognised in alpha- and beta-scruin [PUBMED:7593276, PUBMED:7822422], and in galactose oxidase from the fungus Dactylium dendroides [PUBMED:8126718, PUBMED:2002850]. The structure of galactose oxidase reveals that the repeated sequence corresponds to a 4-stranded anti-parallel beta-sheet motif that forms the repeat unit in a super-barrel structural fold [PUBMED:8182749].
The known functions of kelch-containing proteins are diverse: scruin is an actin cross-linking protein; galactose oxidase catalyses the oxidation of the hydroxyl group at the C6 position in D-galactose; neuraminidase hydrolyses sialic acid residues from glycoproteins; and kelch may have a cytoskeletal function, as it is localised to the actin-rich ring canals that connect the 15 nurse cells to the developing oocyte in Drosophila [PUBMED:7593276]. Nevertheless, based on the location of the kelch pattern in the catalytic unit in galactose oxidase, functionally important residues have been predicted in glyoxal oxidase [PUBMED:8126718].
This entry represents a type of kelch sequence motif that comprises one beta-sheet blade.
The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.
|Molecular function||protein binding (GO:0005515)|
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|Seed source:||Context Domains|
|Number in seed:||42|
|Number in full:||698|
|Average length of the domain:||51.00 aa|
|Average identity of full alignment:||22 %|
|Average coverage of the sequence by the domain:||11.00 %|
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