Summary

Catalytic LigB subunit of aromatic ring-opening dioxygenase

No Pfam abstract.

Literature references

Sugimoto K, Senda T, Aoshima H, Masai E, Fukuda M, Mitsui Y; , Structure Fold Des 1999;7:953-965.: Crystal structure of an aromatic ring opening dioxygenase LigAB, a protocatechuate 4,5-dioxygenase, under aerobic conditions. PUBMED:10467151

InterPro entry IPR004183

Dioxygenases catalyse the incorporation of both atoms of molecular oxygen into substrates using a variety of reaction mechanisms. Cleavage of aromatic rings is one of the most important functions of dioxygenases, which play key roles in the degradation of aromatic compounds. The substrates of ring-cleavage dioxygenases can be classified into two groups according to the mode of scission of the aromatic ring. Intradiol enzymes () use a non-haem Fe(III) to cleave the aromatic ring between two hydroxyl groups (ortho-cleavage), whereas extradiol enzymes use a non-haem Fe(II) to cleave the aromatic ring between a hydroxylated carbon and an adjacent non-hydroxylated carbon (meta-cleavage) PUBMED:10730195, PUBMED:15264822. These two subfamilies differ in sequence, structural fold, iron ligands, and the orientation of second sphere active site amino acid residues. Extradiol dioxygenases are usually homo-multimeric, bind one atom of ferrous ion per subunit and have a subunit size of about 33 kDa. Extradiol dioxygenases can be divided into three classes. Class I and II enzymes () show sequence similarity, with the two-domain class II enzymes having evolved from a class I enzyme through gene duplication. Class III enzymes are different in sequence and structure, but they do share several common active-site characteristics with the class II enzymes, in particular the coordination sphere and the disposition of the putative catalytic base are very similar. Class III enzymes usually have two subunits, designated A and B. This entry represents the extradiol dioxygenase class III enzymes, subunit B.

Enzymes that belong to the extradiol class III family include Protocatechuate 4,5-dioxygenase (4,5-PCD; LigAB) () PUBMED:10467151, of which LigB is represented by this entry; and 2'-aminobiphenyl-2,3-diol 1,2-dioxygenase (CarBaBb) PUBMED:12728990, of which CarBb is represented by this entry.

Clan

This family is a member of clan LigB (CL0283), which contains the following 2 members:

LigB Memo

Gene Ontology

Molecular function	oxidoreductase activity (GO:0016491)
Molecular function	ferrous iron binding (GO:0008198)
Biological process	cellular aromatic compound metabolic process (GO:0006725)

External database links

PANDIT:	PF02900
SCOP:	1bou
SYSTERS:	LigB

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 (47) Full (1222) NCBI (1381) Metagenomics (472)
Viewer:

Formatting options

Alignment:	Seed (47) Full (1222)
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 (47) Full (1222) NCBI (1381) Metagenomics (472)
Full length sequences	Full-sequences (1222)

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:

Structural domain

Previous IDs:

none

Type:

Domain

Author:

Griffiths-Jones SR

Number in seed:

47

Number in full:

1222

Average length of the domain:

258.70 aa

Average identity of full alignment:

23 %

Average coverage of the sequence by the domain:

91.03 %

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	19.8	19.8
Trusted cut-off	19.9	19.8
Noise cut-off	19.5	19.7

Model length:

272

Family (HMM) version:

11

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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Interactions

There are 2 interactions for this family. More...

LigB LigA

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 MSD 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 LigB domain has been found.

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Family: LigB (PF02900)

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