Summary

Cellulose or protein binding domain

This domain is found in two distinct sets of proteins with different functions. Those found in aerobic bacteria bind cellulose (or other carbohydrates); but in anaerobic fungi they are protein binding domains, referred to as dockerin domains or docking domains. They are believed to be responsible for the assembly of a multiprotein cellulase/hemicellulase complex, similar to the cellulosome found in certain anaerobic bacteria.

Literature references

Millward-Sadler SJ, Davidson K, Hazlewood GP, Black GW, Gilbert HJ, Clarke JH; , Biochem J 1995;312:39-48.: Novel cellulose-binding domains, NodB homologues and conserved modular architecture in xylanases from the aerobic soil bacteria Pseudomonas fluorescens subsp. cellulosa and Cellvibrio mixtus. PUBMED:7492333
Raghothama S, Eberhardt RY, Simpson P, Wigelsworth D, White P, Hazlewood GP, Nagy T, Gilbert HJ, Williamson MP; , Nat Struct Biol 2001;8:775-778.: Characterization of a cellulosome dockerin domain from the anaerobic fungus Piromyces equi. PUBMED:11524680
Fillingham IJ, Kroon PA, Williamson G, Gilbert HJ, Hazlewood GP; , Biochem J 1999;343:215-224.: A modular cinnamoyl ester hydrolase from the anaerobic fungus Piromyces equi acts synergistically with xylanase and is part of a multiprotein cellulose-binding cellulase-hemicellulase complex. PUBMED:10493932
Steenbakkers PJ, Li XL, Ximenes EA, Arts JG, Chen H, Ljungdahl LG, Op Den Camp HJ; , J Bacteriol 2001;183:5325-5333.: Noncatalytic docking domains of cellulosomes of anaerobic fungi. PUBMED:11514516

InterPro entry IPR002883

This domain is found in two distinct sets of proteins with different functions. Those found in aerobic bacteria bind cellulose (or other carbohydrates); but in anaerobic fungi they are protein binding domains, referred to as dockerin domains or docking domains. They are believed to be responsible for the assembly of a multiprotein cellulase/hemicellulase complex, similar to the cellulosome found in certain anaerobic bacteria.

The recycling of photosynthetically fixed carbon in plant cell walls is a key microbial process. Enzyme systems that attack the plant cell wall contain noncatalytic carbohydrate-binding modules that mediate attachment to this composite structure and play a pivotal role in maximizing the hydrolytic process. In anaerobes, the degradation is carried out by a high molecular weight, multifunctional complex termed the cellulosome. This consists of a number of independent enzyme components, each of which contains a conserved 40-residue dockerin domain, which functions to bind the enzyme to a cohesin domain within the scaffoldin protein PUBMED:7492333, PUBMED:7493964.

In anaerobic bacteria that degrade plant cell walls, exemplified by Clostridium thermocellum, the dockerin domains of the catalytic polypeptides can bind equally well to any cohesin from the same organism. More recently, anaerobic fungi, typified by Piromyces equi, have been suggested to also synthesise a cellulosome complex, although the dockerin sequences of the bacterial and fungal enzymes are completely different PUBMED:11524680. For example, the fungal enzymes contain one, two or three copies of the dockerin sequence in tandem within the catalytic polypeptide. In contrast, all the C. thermocellum cellulosome catalytic components contain a single dockerin domain. The anaerobic bacterial dockerins are homologous to EF hands (calcium-binding motifs) and require calcium for activity whereas the fungal dockerin does not require calcium. Finally, the interaction between cohesin and dockerin appears to be species specific in bacteria, there is almost no species specificity of binding within fungal species and no identified sites that distinguish different species.

The structure of dockerin from P. equi contains two helical stretches and four short beta-strands which form an antiparallel sheet structure adjacent to an additional short twisted parallel strand. The N- and C-termini are adjacent to each other.

Aerobic bacteria contain related regions, however these appear to function as cellulose/carbohydrate binding domains.

Gene Ontology

Molecular function	hydrolase activity, hydrolyzing O-glycosyl compounds (GO:0004553)
Biological process	carbohydrate metabolic process (GO:0005975)

External database links

CAZY:	CBM_10
PANDIT:	PF02013
SCOP:	1qld
SYSTERS:	CBM_10

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 (92) Full (216) NCBI (271) Metagenomics
Viewer:

Formatting options

Alignment:	Seed (92) Full (216)
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 (92) Full (216) NCBI (271) Metagenomics
Full length sequences	Full-sequences (216)

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:

PSI-BLAST P10476/668-713

Previous IDs:

CBD_5;

Type:

Domain

Author:

Bateman A

Number in seed:

92

Number in full:

216

Average length of the domain:

34.40 aa

Average identity of full alignment:

42 %

Average coverage of the sequence by the domain:

6.34 %

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	21.0	21.0
Trusted cut-off	21.8	22.9
Noise cut-off	19.5	20.5

Model length:

36

Family (HMM) version:

9

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...

Interactions

There is 1 interaction for this family. More...

CBM_10

Structures

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 CBM_10 domain has been found.

Loading structure mapping...

Family: CBM_10 (PF02013)

Jump to...