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1934  structures 2775  species 0  interactions 426470  sequences 9824  architectures

Family: LRR_8 (PF13855)

Summary: Leucine rich repeat

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

Leucine-rich repeat Edit Wikipedia article

An example of a leucine-rich repeat protein, a porcine ribonuclease inhibitor (PDB ID 2BNH).

A leucine-rich repeat (LRR) is a protein structural motif that forms an α/β horseshoe fold. It is composed of repeating 20-30 amino acid stretches that are unusually rich in the hydrophobic amino acid leucine. 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 tighly sterically packed with leucine residues.


Leucine-rich repeat motifs have been identified in a large number of functionally unrelated proteins. The best-known example is the ribonuclease inhibitor, but other proteins such as the tropomyosin regulator tropomodulin also share the motif.

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.

External links


  • Branden C, Tooze J. (1999). Introduction to Protein Structure 2nd ed. Garland Publishing: New York, NY.

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

No Pfam abstract.

Internal database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR001611

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 ].

Gene Ontology

The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.

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.

Representative proteomes UniProt
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Representative proteomes UniProt

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We make all of our alignments available in Stockholm format. You can download them here as raw, plain text files or as gzip-compressed files.

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

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...


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.

Note: You can also download the data file for the tree.

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: Jackhmer:JCS-Target417241
Previous IDs: none
Type: Repeat
Sequence Ontology: SO:0001068
Author: Coggill P
Number in seed: 62
Number in full: 426470
Average length of the domain: 59.1 aa
Average identity of full alignment: 28 %
Average coverage of the sequence by the domain: 20.85 %

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 27.0 27.0
Trusted cut-off 27.0 27.0
Noise cut-off 26.9 26.9
Model length: 61
Family (HMM) version: 9
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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This visualisation provides a simple graphical representation of the distribution of this family across species. You can find the original interactive tree in the adjacent tab. More...

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For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the LRR_8 domain has been found. There are 1934 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein 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
A0A044QJN0 View 3D Structure Click here
A0A044R6P6 View 3D Structure Click here
A0A044R8Y5 View 3D Structure Click here
A0A044R999 View 3D Structure Click here
A0A044S3Q3 View 3D Structure Click here
A0A044SB21 View 3D Structure Click here
A0A044SN00 View 3D Structure Click here
A0A044SZE0 View 3D Structure Click here
A0A044T3S7 View 3D Structure Click here
A0A044T4Z0 View 3D Structure Click here
A0A044T6G0 View 3D Structure Click here
A0A044TAZ4 View 3D Structure Click here
A0A044TEZ1 View 3D Structure Click here
A0A044TGV4 View 3D Structure Click here
A0A044TJA8 View 3D Structure Click here
A0A044TM04 View 3D Structure Click here
A0A044TMW2 View 3D Structure Click here
A0A044TMW5 View 3D Structure Click here
A0A044TMW9 View 3D Structure Click here
A0A044TYG7 View 3D Structure Click here
A0A044U7M9 View 3D Structure Click here
A0A044U9V0 View 3D Structure Click here
A0A044UIA8 View 3D Structure Click here
A0A044UX15 View 3D Structure Click here
A0A044UYZ0 View 3D Structure Click here
A0A044UZ90 View 3D Structure Click here
A0A044V751 View 3D Structure Click here
A0A044V9J4 View 3D Structure Click here
A0A044VDX9 View 3D Structure Click here
A0A077YVH5 View 3D Structure Click here
A0A077YVQ7 View 3D Structure Click here
A0A077YWH1 View 3D Structure Click here
A0A077YZ14 View 3D Structure Click here
A0A077YZC5 View 3D Structure Click here
A0A077Z045 View 3D Structure Click here
A0A077Z106 View 3D Structure Click here
A0A077Z151 View 3D Structure Click here
A0A077Z174 View 3D Structure Click here
A0A077Z1K5 View 3D Structure Click here
A0A077Z1Q4 View 3D Structure Click here