Summary

PPR repeat

This repeat has no known function. It is about 35 amino acids long and found in up to 18 copies in some proteins. This family appears to be greatly expanded in plants. This repeat occurs in PET309 P32522 that may be involved in RNA stabilisation [1]. This domain occurs in crp1 that is involved in RNA processing [2]. This repeat is associated with a predicted plant protein O49549 that has a domain organisation similar to the human BRCA1 protein. The repeat has been called PPR [3].

Literature references

Manthey GM, McEwen JE; , EMBO J 1995;14:4031-4043.: The product of the nuclear gene PET309 is required for translation of mature mRNA and stability or production of intron-containing RNAs derived from the mitochondrial COX1 locus of Saccharomyces cerevisiae. PUBMED:7664742
Barkan A, Walker M, Nolasco M, Johnson D; , EMBO J 1994;13:3170-3181.: A nuclear mutation in maize blocks the processing and translation of several chloroplast mRNAs and provides evidence for the differential translation of alternative mRNA forms. PUBMED:8039510
Small ID, Peeters I; , Trends Biochem Sci 2000;25:45-47.: The PPR motif - a TPR-related motif prevalent in plant organellar proteins. PUBMED:10664580

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 ) PUBMED:10664580.

The plant PPR protein family has been divided in two subfamilies on the basis of their motif content and organisation PUBMED:15269332, PUBMED:17560114.

Examples of PPR repeat-containing proteins include PET309 , 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 that has a domain organisation similar to the human BRCA1 protein.

Clan

This family is a member of clan TPR (CL0020), which contains the following 67 members:

Adaptin_N Arm Avirulence BTAD ChAPs CLASP_N Clathrin Clathrin-link Clathrin_propel Coatomer_E Cohesin_load CRM1_C Cse1 DNA_alkylation Drf_FH3 Drf_GBD DUF2225 DUF634 DUF654 FAT GUN4 HAT HEAT HEAT_PBS HemY_N IBB IBN_N IFRD IML2 KAP Leuk-A4-hydro_C LRV LRV_FeS MA3 MIF4G MIF4G_like MIF4G_like_2 Mo25 Neurochondrin NSF Paf67 ParcG PC_rep PHAT PI3Ka PPR Proteasom_PSMB PUF Rapsyn_N RPN7 Sel1 SHNi-TPR SPO22 ST7 Suf SusD TOM20_plant TPR_1 TPR_2 TPR_3 TPR_4 Upf2 V-ATPase_H_C V-ATPase_H_N Vps39_1 W2 Xpo1

External database links

PANDIT:	PF01535
SYSTERS:	PPR

Domain organisation

Below is a listing of the unique domain organisations or architectures in which this domain is found. More...

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Alignments

There are various ways to view or download the sequence alignments that we store. You can use a sequence viewer to look at either the seed or full alignment for the family, or you can look at a plain text version of the sequence in a variety of different formats. More...

View options

Alignment:	Seed (518) Full (36723) NCBI (62970) Metagenomics (976)
Viewer:

Formatting options

Alignment:	Seed (518) Full (36723)
Format:
Order:	Tree Alphabetical
Sequence:	Inserts lower case All upper case
Gaps:
Download/view:	Download View

Download options

Very large alignments can often cause problems for the formatting tool above. If you find that downloading or viewing a large alignment is problematic, you can also download a gzip-compressed, Stockholm-format file containing the seed or full alignment for this family.

You can also download a FASTA format file containing the full-length sequences for all sequences in the full alignment.

The main seed and full alignments are generated using sequences from the UniProt sequence database. However, we also generate alignments using sequences from the NCBI sequence database and the "metaseq" metagenomics dataset.

You can view alignments from these two additional datasets using the form above, or you can download alignments of NCBI or metagenomics sequences, as gzip-compressed files.

Pfam alignments:	Seed (518) Full (36723) NCBI (62970) Metagenomics (976)
Full length sequences	Full-sequences (36723)

External links

MyHits provides a collection of tools to handle multiple sequence alignments. For example, one can refine a seed alignment (sequence addition or removal, re-alignment or manual edition) and then search databases for remote homologs using HMMER2.

HMM logo

HMM logos is one way of visualising profile HMMs. Logos provide a quick overview of the properties of an HMM in a graphical form. You can see a more detailed description of HMM logos and find out how you can interpret them here. More...

Trees

This page displays the phylogenetic tree for this family. We use FastTree to calculate neighbour join trees with a local bootstrap based on 100 resamples (shown next to the tree nodes). FastTree calculates approximately-maximum-likelihood phylogenetic trees from our seed or full alignments.

Note: You can also download the data files for the seed, full, NCBI or metagenomics trees.

Curation and family details

This section shows the detailed information about the Pfam family. You can see the definitions of many of the terms in this section in the glossary and a fuller explanation of the scoring system that we use in the scores section of the help pages.

Curation

Seed source:

Pfam-B_874 (release 4.0)

Previous IDs:

DUF17;

Type:

Family

Author:

Bateman A, Birney E

Number in seed:

518

Number in full:

36723

Average length of the domain:

30.10 aa

Average identity of full alignment:

22 %

Average coverage of the sequence by the domain:

4.45 %

HMM information

HMM build commands:

build method: hmmbuild -o /dev/null HMM SEED

search method: hmmsearch -Z 9421015 -E 1000 HMM pfamseq

Model details:

Parameter	Sequence	Domain
Gathering cut-off	25.0	9.3
Trusted cut-off	25.0	9.3
Noise cut-off	24.9	9.2

Model length:

31

Family (HMM) version:

13

Download:

download the raw HMM for this family

Species distribution

Tree controls

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The tree shows the occurrence of this domain across different species. More...

Species trees

We show the species tree in one of two ways. For smaller trees we try to show an interactive representation, which allows you to select specific nodes in the tree and view them as an alignment or as a set of Pfam domain graphics.

Unfortunately we have found that there are problems viewing the interactive tree when the it becomes larger than a certain limit. Furthermore, we have found that Internet Explorer can become unresponsive when viewing some trees, regardless of their size. We therefore show a text representation of the species tree when the size is above a certain limit or if you are using Internet Explorer to view the site.

If you are using IE you can still load the interactive tree by clicking the "Generate interactive tree" button, but please be aware of the potential problems that the interactive species tree can cause.

Interactive tree

For all of the domain matches in a full alignment, we count the number that are found on all sequences in the alignment. This total is shown in the purple box.

We also count the number of unique sequences on which each domain is found, which is shown in green. Note that a domain may appear multiple times on the same sequence, leading to the difference between these two numbers.

Finally, we group sequences from the same organism according to the NCBI code that is assigned by UniProt, allowing us to count the number of distinct sequences on which the domain is found. This value is shown in the pink boxes.

We use the NCBI species tree to group organisms according to their taxonomy and this forms the structure of the displayed tree. Note that in some cases the trees are too large (have too many nodes) to allow us to build an interactive tree, but in most cases you can still view the tree in a plain text, non-interactive representation. Those species which are represented in the seed alignment for this domain are highlighted.

You can use the tree controls to manipulate how the interactive tree is displayed:

show/hide the summary boxes
highlight species that are represented in the seed alignment
expand/collapse the tree or expand it to a given depth
select a sub-tree or a set of species within the tree and view them graphically or as an alignment
save a plain text representation of the tree

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Family: PPR (PF01535)

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