Summary

Insect cuticle protein

Many insect cuticular proteins include a 35-36 amino acid motif known as the R&R consensus. The extensive conservation of this region led to the suggestion that it functions to bind chitin. Provocatively, it has no sequence similarity to the well-known cysteine-containing chitin-binding domain found in chitinases and some peritrophic membrane proteins. Chitin binding has been shown experimentally for this region [1]. Thus arthropods have two distinct classes of chitin binding proteins, those with the chitin-binding domain found in lectins, chitinases and peritrophic membranes (cysCBD) and those with the cuticular protein chitin-binding domain (non-cysCBD) [1].

Literature references

Rebers JE, Willis JH; , Insect Biochem Mol Biol 2001;31:1083-1093.: A conserved domain in arthropod cuticular proteins binds chitin. PUBMED:11520687

InterPro entry IPR000618

Insect cuticle is composed of proteins and chitin. The cuticular proteins seem to be specific to the type of cuticle (flexible or stiff) that occur at stages of the insect development. The proteins found in the flexible cuticle of larva and pupa of different insects share a conserved C-terminal section PUBMED:2462055 such a region is also found in the soft endocuticle of adults insects PUBMED:1997327 as well as in other cuticular proteins including in arachnids PUBMED:9014336. In addition, cuticular proteins share hydrophobic regions dominated by tetrapeptide repeats (A-A-P-A/V), which are presumed to be functionally important PUBMED:1997327, PUBMED:9066122. Many insect cuticle proteins also include a 35-36 amino acid motif known as the R and R consensus. An extended form of this motif has been shown PUBMED:11520687 to bind chitin. It has no sequence similiarity to the cysteine-containing chitin-binding domain of chitinases and some peritrophic membrane proteins, suggesting that arthropods have two distinct classes of chitin-binding proteins, those with the chitin-binding domains found in lectins, chitinases and peritrophic membranes (cysCBD), and those with the type of chitin-binding domains found in cuticular proteins (non-cysCBD) PUBMED:11520687.

The cuticle protein signature has been found in locust cuticle proteins 7 (LM-7), 8 (LM-8), 19 (LM-19) and endocuticle structural glycoprotein ABD-4; Hyalophora cecropia (Cecropia moth) cuticle proteins 12 and 66; Drosophila melanogaster (Fruit fly) larval cuticles proteins I, II, III and IV (LCP1 to LCP4); drosophila pupal cuticle proteins PCP, EDG-78E and EDG-84E; Manduca sexta (Tobacco hawkmoth) cuticle protein LCP-14; Tenebrio molitor (Yellow mealworm) cuticle proteins ACP-20, A1A, A2B and A3A; and Araneus diadematus (Spider) cuticle proteins ACP 11.9, ACP 12.4, ACP 12.6, ACP 15.5 and ACP 15.7.

Gene Ontology

Molecular function

structural constituent of cuticle (GO:0042302)

External database links

PANDIT:	PF00379
PROSITE:	PDOC00206
SYSTERS:	Chitin_bind_4

Domain organisation

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

Loading domain graphics...

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 (159) Full (2524) NCBI (2519) Metagenomics (1)
Viewer:

Formatting options

Alignment:	Seed (159) Full (2524)
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 (159) Full (2524) NCBI (2519) Metagenomics (1)
Full length sequences	Full-sequences (2524)

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:

Prosite

Previous IDs:

insect_cuticle;

Type:

Family

Author:

Finn RD

Number in seed:

159

Number in full:

2524

Average length of the domain:

53.00 aa

Average identity of full alignment:

33 %

Average coverage of the sequence by the domain:

23.97 %

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	21.5	21.5
Trusted cut-off	21.6	21.5
Noise cut-off	21.3	21.4

Model length:

51

Family (HMM) version:

16

Download:

download the raw HMM for this family

Species distribution

Tree controls

Hide

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

Loading...

Family: Chitin_bind_4 (PF00379)

Jump to...