Summary: Pentatricopeptide repeat domain
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Pentatricopeptide repeat Edit Wikipedia article
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The pentatricopeptide repeat (PPR) is a 35-amino acid sequence motif. Pentatricopeptide repeat containing proteins are a family of proteins commonly found in the plant kingdom. They are distinguished by the presence of tandem degenerate PPR motifs and by the relative lack of introns in the genes coding for them.
Approximately 450 such proteins have been identified in the arabidopsis genome, and another 477 in the rice genome. Despite the large size of the protein family, genetic data suggest that there is little or no redundancy of function between the PPR proteins in arabidopsis.
The purpose of PPR proteins is currently under dispute. It has been shown that a good deal of those in Arabidopsis interact (often essentially) with mitochondria and other organelles and that they are possibly involved in RNA editing. However many trans proteins are required for this editing to occur and research continues to look at which proteins are needed.
Human genes encoding proteins containing this repeat include:
- ^ Mingler MK, Hingst AM, Clement SL, Yu LE, Reifur L, Koslowsky DJ (November 2006). "Identification of pentatricopeptide repeat proteins in Trypanosoma brucei". Mol. Biochem. Parasitol. 150 (1): 3745. doi:10.1016/j.molbiopara.2006.06.006. PMID 16837079.
- ^ a b c Lurin C, Andrés C, Aubourg S, Bellaoui M, Bitton F, Bruyère C, Caboche M, Debast C, Gualberto J, Hoffmann B, Lecharny A, Le Ret M, Martin-Magniette ML, Mireau H, Peeters N, Renou JP, Szurek B, Taconnat L, Small I (August 2004). "Genome-wide analysis of Arabidopsis pentatricopeptide repeat proteins reveals their essential role in organelle biogenesis". Plant Cell 16 (8): 2089103. doi:10.1105/tpc.104.022236. PMC 519200. PMID 15269332. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=519200.
- ^ O'Toole N, Hattori M, Andres C, Iida K, Lurin C, Schmitz-Linneweber C, Sugita M, Small I (June 2008). "On the expansion of the pentatricopeptide repeat gene family in plants". Mol. Biol. Evol. 25 (6): 11208. doi:10.1093/molbev/msn057. PMID 18343892.
- ^ Kotera E, Tasaka M, Shikanai T (January 2005). "A pentatricopeptide repeat protein is essential for RNA editing in chloroplasts". Nature 433 (7023): 32630. doi:10.1038/nature03229. PMID 15662426.
- ^ Takenaka M, Verbitskiy D, Zehrmann A, Brennicke A (June 2010). "Reverse genetic screening identifies five E-class PPR-proteins involved in RNA editing in mitochondria of Arabidopsis Thaliana". J Biol Chem 285 (35): 2712227129. doi:10.1074/jbc.M110.128611. PMC 2930711. PMID 20566637. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2930711.
- ^ Small ID, Peeters N (February 2000). "The PPR motif - a TPR-related motif prevalent in plant organellar proteins". Trends Biochem. Sci. 25 (2): 467. PMID 10664580.
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Pentatricopeptide repeat domain Provide feedback
This family matches additional variants of the PPR repeat that were not captured by the model for PF01535. The exact function is not known.
Internal database links
|Similarity to PfamA using HHSearch:||PPR PPR_1 PPR_2 TPR_14|
External database links
This tab holds annotation information from the InterPro database.
InterPro entry IPR002885
This entry represents the PPR repeat.
Pentatricopeptide repeat (PPR) proteins are characterised by tandem repeats of a degenerate 35 amino acid motif [PUBMED:10664580]. Most of PPR proteins have roles in mitochondria or plastid [PUBMED:15270678]. PPR repeats were discovered while screening Arabidopsis proteins for those predicted to be targeted to mitochondria or chloroplast [PUBMED:10664580, PUBMED:15269332]. Some of these proteins have been shown to play a role in post-transcriptional processes within organelles and they are thought to be sequence-specific RNA-binding proteins [PUBMED:12782738, PUBMED:12832482, PUBMED:18031283]. Plant genomes have between one hundred to five hundred PPR genes per genome whereas non-plant genomes encode two to six PPR proteins.
Although no PPR structures are yet known, the motif is predicted to fold into a helix-turn-helix structure similar to those found in the tetratricopeptide repeat (TPR) family (see PROSITEDOC) [PUBMED:10664580].
Examples of PPR repeat-containing proteins include PET309 SWISSPROT, which may be involved in RNA stabilisation [PUBMED:7664742], and crp1, which is involved in RNA processing [PUBMED:8039510]. The repeat is associated with a predicted plant protein SWISSPROT that has a domain organisation similar to the human BRCA1 protein.
- the number of sequences which exhibit this architecture
a textual description of the architecture, e.g. Gla, EGF x 2, Trypsin.
This example describes an architecture with one
Gladomain, followed by two consecutive
EGFdomains, and finally a single
- the UniProt description of the protein sequence
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We make a range of alignments for each Pfam-A family:
- the curated alignment from which the HMM for the family is built
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- Representative Proteomes (RPs) at 15%, 35%, 55% and 75% co-membership thresholds
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1Cannot generate PP/Heatmap alignments for seeds; no PP data available
Key: available, not generated, — not available.
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Curation and family details
|Number in seed:||132|
|Number in full:||5769|
|Average length of the domain:||33.00 aa|
|Average identity of full alignment:||18 %|
|Average coverage of the sequence by the domain:||6.79 %|
|HMM build commands:||
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 23193494 -E 1000 --cpu 4 HMM pfamseq
|Family (HMM) version:||1|
|Download:||download the raw HMM for this family|
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