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0  structures 148  species 0  interactions 3198  sequences 163  architectures

Family: LRR_2 (PF07723)

Summary: Leucine Rich Repeat

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This is the Wikipedia entry entitled "Leucine-rich repeat". More...

Leucine-rich repeat Edit Wikipedia article

2bnh topview.png
An example of a leucine-rich repeat protein, a porcine ribonuclease inhibitor
Pfam clanCL0022
Leucine rich repeat variant
PDB 1lrv EBI.jpg
a leucine-rich repeat variant with a novel repetitive protein structural motif
Pfam clanCL0020
LRR adjacent
PDB 1h6u EBI.jpg
internalin h: crystal structure of fused n-terminal domains.
Leucine rich repeat N-terminal domain
PDB 1xec EBI.jpg
dimeric bovine tissue-extracted decorin, crystal form 2
Leucine rich repeat N-terminal domain
PDB 1ogq EBI.jpg
the crystal structure of pgip (polygalacturonase inhibiting protein), a leucine rich repeat protein involved in plant defense
Leucine rich repeat C-terminal domain
PDB 1w8a EBI.jpg
third lrr domain of drosophila slit
LRV protein FeS4 cluster
PDB 1lrv EBI.jpg
a leucine-rich repeat variant with a novel repetitive protein structural motif
Pfam clanCL0020

A leucine-rich repeat (LRR) is a protein structural motif that forms an α/β horseshoe fold.[1][2] It is composed of repeating 20–30 amino acid stretches that are unusually rich in the hydrophobic amino acid leucine. These tandem repeats commonly fold together to form a solenoid protein domain, termed leucine-rich repeat domain. Typically, each repeat unit has beta strand-turn-alpha helix structure, and the assembled domain, composed of many such repeats, has a horseshoe shape with an interior parallel beta sheet and an exterior array of helices. One face of the beta sheet and one side of the helix array are exposed to solvent and are therefore dominated by hydrophilic residues. The region between the helices and sheets is the protein's hydrophobic core and is tightly sterically packed with leucine residues.

Leucine-rich repeats are frequently involved in the formation of protein–protein interactions.[3][4]


Leucine-rich repeat motifs have been identified in a large number of functionally unrelated proteins.[5] The best-known example is the ribonuclease inhibitor, but other proteins such as the tropomyosin regulator tropomodulin and the toll-like receptor also share the motif. In fact, the toll-like receptor possesses 10 successive LRR motifs which serve to bind pathogen- and danger-associated molecular patterns.

Although the canonical LRR protein contains approximately one helix for every beta strand, variants that form beta-alpha superhelix folds sometimes have long loops rather than helices linking successive beta strands.

One leucine-rich repeat variant domain (LRV) has a novel repetitive structural motif consisting of alternating alpha- and 310-helices arranged in a right-handed superhelix, with the absence of the beta-sheets present in other leucine-rich repeats.[6]

Associated domains

Leucine-rich repeats are often flanked by N-terminal and C-terminal cysteine-rich domains, but not always as is the case with C5orf36

They also co-occur with LRR adjacent domains. These are small, all beta strand domains, which have been structurally described for the protein Internalin (InlA) and related proteins InlB, InlE, InlH from the pathogenic bacterium Listeria monocytogenes. Their function appears to be mainly structural: They are fused to the C-terminal end of leucine-rich repeats, significantly stabilising the LRR, and forming a common rigid entity with the LRR. They are themselves not involved in protein-protein-interactions but help to present the adjacent LRR-domain for this purpose. These domains belong to the family of Ig-like domains in that they consist of two sandwiched beta sheets that follow the classical connectivity of Ig-domains. The beta strands in one of the sheets is, however, much smaller than in most standard Ig-like domains, making it somewhat of an outlier.[7][8][9]

An iron sulphur cluster is found at the N-terminus of some proteins containing the leucine-rich repeat variant domain (LRV). These proteins have a two-domain structure, composed of a small N-terminal domain containing a cluster of four Cysteine residues that houses the 4Fe:4S cluster, and a larger C-terminal domain containing the LRV repeats.[6] Biochemical studies revealed that the 4Fe:4S cluster is sensitive to oxygen, but does not appear to have reversible redox activity.

See also


  1. ^ Kobe B, Deisenhofer J (October 1994). "The leucine-rich repeat: a versatile binding motif". Trends Biochem. Sci. 19 (10): 415–21. doi:10.1016/0968-0004(94)90090-6. PMID 7817399.
  2. ^ Enkhbayar P, Kamiya M, Osaki M, Matsumoto T, Matsushima N (February 2004). "Structural principles of leucine-rich repeat (LRR) proteins". Proteins. 54 (3): 394–403. doi:10.1002/prot.10605. PMID 14747988.
  3. ^ Kobe B, Kajava AV (December 2001). "The leucine-rich repeat as a protein recognition motif". Curr. Opin. Struct. Biol. 11 (6): 725–32. doi:10.1016/S0959-440X(01)00266-4. PMID 11751054.
  4. ^ Gay NJ, Packman LC, Weldon MA, Barna JC (October 1991). "A leucine-rich repeat peptide derived from the Drosophila Toll receptor forms extended filaments with a beta-sheet structure". FEBS Lett. 291 (1): 87–91. doi:10.1016/0014-5793(91)81110-T. PMID 1657640.
  5. ^ Rothberg JM, Jacobs JR, Goodman CS, Artavanis-Tsakonas S (December 1990). "slit: an extracellular protein necessary for development of midline glia and commissural axon pathways contains both EGF and LRR domains". Genes Dev. 4 (12A): 2169–87. doi:10.1101/gad.4.12a.2169. PMID 2176636.
  6. ^ a b Peters JW, Stowell MH, Rees DC (December 1996). "A leucine-rich repeat variant with a novel repetitive protein structural motif". Nat. Struct. Biol. 3 (12): 991–4. doi:10.1038/nsb1296-991. PMID 8946850.
  7. ^ Schubert WD, Gobel G, Diepholz M, Darji A, Kloer D, Hain T, Chakraborty T, Wehland J, Domann E, Heinz DW (September 2001). "Internalins from the human pathogen Listeria monocytogenes combine three distinct folds into a contiguous internalin domain". J. Mol. Biol. 312 (4): 783–94. doi:10.1006/jmbi.2001.4989. PMID 11575932.
  8. ^ Schubert WD, Urbanke C, Ziehm T, Beier V, Machner MP, Domann E, Wehland J, Chakraborty T, Heinz DW (December 2002). "Structure of internalin, a major invasion protein of Listeria monocytogenes, in complex with its human receptor E-cadherin". Cell. 111 (6): 825–36. doi:10.1016/S0092-8674(02)01136-4. PMID 12526809.
  9. ^ Freiberg A, Machner MP, Pfeil W, Schubert WD, Heinz DW, Seckler R (March 2004). "Folding and stability of the leucine-rich repeat domain of internalin B from Listeri monocytogenes". J. Mol. Biol. 337 (2): 453–61. doi:10.1016/j.jmb.2004.01.044. PMID 15003459.

Further reading

External links

This article incorporates text from the public domain Pfam and InterPro: IPR012569
This article incorporates text from the public domain Pfam and InterPro: IPR013210
This article incorporates text from the public domain Pfam and InterPro: IPR000372
This article incorporates text from the public domain Pfam and InterPro: IPR000483
This article incorporates text from the public domain Pfam and InterPro: IPR004830
This article incorporates text from the public domain Pfam and InterPro: IPR004830

This page is based on a Wikipedia article. The text is available under the Creative Commons Attribution/Share-Alike License.

This tab holds the annotation information that is stored in the Pfam database. As we move to using Wikipedia as our main source of annotation, the contents of this tab will be gradually replaced by the Wikipedia tab.

Leucine Rich Repeat Provide feedback

This Pfam entry includes some LRRs that fail to be detected with the PF00560 model.

Literature references

  1. Kobe B, Deisenhofer J; , Trends Biochem Sci 1994;19:415-421.: The leucine-rich repeat: a versatile binding motif. PUBMED:7817399 EPMC:7817399

  2. Kobe B, Deisenhofer J; , Nature 1993;366:751-756.: Crystal structure of porcine ribonuclease inhibitor, a protein with leucine-rich repeats. PUBMED:8264799 EPMC:8264799

This tab holds annotation information from the InterPro database.

InterPro entry IPR013101

Leucine-rich repeats (LRR) consist of 2-45 motifs of 20-30 amino acids in length that generally folds into an arc or horseshoe shape [ PUBMED:14747988 ]. LRRs occur in proteins ranging from viruses to eukaryotes, and appear to provide a structural framework for the formation of protein-protein interactions [ PUBMED:11751054 , PUBMED:1657640 ].Proteins containing LRRs include tyrosine kinase receptors, cell-adhesion molecules, virulence factors, and extracellular matrix-binding glycoproteins, and are involved in a variety of biological processes, including signal transduction, cell adhesion, DNA repair, recombination, transcription, RNA processing, disease resistance, apoptosis, and the immune response [ PUBMED:2176636 , PUBMED:21606681 ].

Sequence analyses of LRR proteins suggested the existence of several different subfamilies of LRRs. The significance of this classification is that repeats from different subfamilies never occur simultaneously and have most probably evolved independently. It is, however, now clear that all major classes of LRR have curved horseshoe structures with a parallel beta sheet on the concave side and mostly helical elements on the convex side. At least six families of LRR proteins, characterised by different lengths and consensus sequences of the repeats, have been identified. Eleven-residue segments of the LRRs (LxxLxLxxN/CxL), corresponding to the beta-strand and adjacent loop regions, are conserved in LRR proteins, whereas the remaining parts of the repeats (herein termed variable) may be very different. Despite the differences, each of the variable parts contains two half-turns at both ends and a "linear" segment (as the chain follows a linear path overall), usually formed by a helix, in the middle. The concave face and the adjacent loops are the most common protein interaction surfaces on LRR proteins. 3D structure of some LRR proteins-ligand complexes show that the concave surface of LRR domain is ideal for interaction with alpha-helix, thus supporting earlier conclusions that the elongated and curved LRR structure provides an outstanding framework for achieving diverse protein-protein interactions [ PUBMED:11751054 ]. Molecular modeling suggests that the conserved pattern LxxLxL, which is shorter than the previously proposed LxxLxLxxN/CxL is sufficient to impart the characteristic horseshoe curvature to proteins with 20- to 30-residue repeats [ PUBMED:11967365 ].

This entry includes some LRRs that fail to be detected by INTERPRO [ PUBMED:7817399 , PUBMED:8264799 ].

Domain organisation

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

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Pfam Clan

This family is a member of clan LRR (CL0022), which has the following description:

Each Leucine Rich Repeat is composed of a beta-alpha unit. These units form elongated non-globular structures. Leucine Rich Repeats are often flanked by cysteine rich domains. This Pfam entry contains Leucine Rich Repeats not recognised by the Pfam:PF00560 model.

The clan contains the following 18 members:

DUF285 FBXL18_LRR FNIP LRR_1 LRR_10 LRR_11 LRR_12 LRR_2 LRR_3 LRR_4 LRR_5 LRR_6 LRR_8 LRR_9 LRR_RI_capping Recep_L_domain Transp_inhibit TTSSLRR


We store a range of different sequence alignments for families. As well as the seed alignment from which the family is built, we provide the full alignment, generated by searching the sequence database (reference proteomes) using the family HMM. We also generate alignments using four representative proteomes (RP) sets and the UniProtKB sequence database. More...

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We make a range of alignments for each Pfam-A family. You can see a description of each above. You can view these alignments in various ways but please note that some types of alignment are never generated while others may not be available for all families, most commonly because the alignments are too large to handle.

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

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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...


This page displays the phylogenetic tree for this family's seed alignment. 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 alignment.

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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 View help on the curation process

Seed source: PfamB-152 (release 14.0)
Previous IDs: none
Type: Repeat
Sequence Ontology: SO:0001068
Author: Studholme DJ
Number in seed: 141
Number in full: 3198
Average length of the domain: 25.70 aa
Average identity of full alignment: 37 %
Average coverage of the sequence by the domain: 6.33 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 61295632 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 20.9 9.5
Trusted cut-off 20.9 9.5
Noise cut-off 20.8 9.4
Model length: 26
Family (HMM) version: 16
Download: download the raw HMM for this family

Species distribution

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Colour assignments

Archea Archea Eukaryota Eukaryota
Bacteria Bacteria Other sequences Other sequences
Viruses Viruses Unclassified Unclassified
Viroids Viroids Unclassified sequence Unclassified sequence


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AlphaFold Structure Predictions

The list of proteins below match this family and have AlphaFold predicted structures. Click on the protein accession to view the predicted structure.

Protein Predicted structure External Information
A0A0R0F0P8 View 3D Structure Click here
A0A1I9LSS0 View 3D Structure Click here
A0A1P8BAY2 View 3D Structure Click here
A0A1P8BG75 View 3D Structure Click here
B9FKP4 View 3D Structure Click here
F4HP61 View 3D Structure Click here
F4HR18 View 3D Structure Click here
F4J826 View 3D Structure Click here
F4JLN7 View 3D Structure Click here
F4KIR0 View 3D Structure Click here
I1N257 View 3D Structure Click here
K7L5U7 View 3D Structure Click here
K7MNT6 View 3D Structure Click here
O23360 View 3D Structure Click here
O80741 View 3D Structure Click here
P0C2F8 View 3D Structure Click here
P0C2G1 View 3D Structure Click here
P0C2G6 View 3D Structure Click here
Q0JEI7 View 3D Structure Click here
Q0V7P8 View 3D Structure Click here
Q0WR05 View 3D Structure Click here
Q1PDU4 View 3D Structure Click here
Q1PED9 View 3D Structure Click here
Q1PEY8 View 3D Structure Click here
Q1PFI4 View 3D Structure Click here
Q1PFK0 View 3D Structure Click here
Q2V3N5 View 3D Structure Click here
Q3E7K7 View 3D Structure Click here
Q3E944 View 3D Structure Click here
Q3EA38 View 3D Structure Click here
Q3EAE5 View 3D Structure Click here
Q4PSI6 View 3D Structure Click here
Q501B7 View 3D Structure Click here
Q501E9 View 3D Structure Click here
Q56W59 View 3D Structure Click here
Q56XS8 View 3D Structure Click here
Q6DBN6 View 3D Structure Click here
Q6DR13 View 3D Structure Click here
Q6NKX3 View 3D Structure Click here
Q84RK6 View 3D Structure Click here

trRosetta Structure

The structural model below was generated by the Baker group with the trRosetta software using the Pfam UniProt multiple sequence alignment.

The InterPro website shows the contact map for the Pfam SEED alignment. Hovering or clicking on a contact position will highlight its connection to other residues in the alignment, as well as on the 3D structure.

Improved protein structure prediction using predicted inter-residue orientations. Jianyi Yang, Ivan Anishchenko, Hahnbeom Park, Zhenling Peng, Sergey Ovchinnikov, David Baker Proceedings of the National Academy of Sciences Jan 2020, 117 (3) 1496-1503; DOI: 10.1073/pnas.1914677117;