Please note: this site relies heavily on the use of javascript. Without a javascript-enabled browser, this site will not function correctly. Please enable javascript and reload the page, or switch to a different browser.
61  structures 590  species 2  interactions 768  sequences 6  architectures

Family: CAT (PF00302)

Summary: Chloramphenicol acetyltransferase

Pfam includes annotations and additional family information from a range of different sources. These sources can be accessed via the tabs below.

This is the Wikipedia entry entitled "Chloramphenicol acetyltransferase". More...

Chloramphenicol acetyltransferase Edit Wikipedia article

Chloramphenicol acetyltransferase
Chloramphenicol acetyltransferase 3CLA transparent.png
Ribbon diagram of the chloramphenicol acetyltransferase trimer with chloramphenicol bound. From PDB 3CLA.
Identifiers
Symbol CAT
Pfam PF00302
InterPro IPR001707
PROSITE PDOC00093
SCOP 3cla
SUPERFAMILY 3cla
Chloramphenicol acetyltransferase
Identifiers
EC number 2.3.1.28
CAS number 9040-07-7
Databases
IntEnz IntEnz view
BRENDA BRENDA entry
ExPASy NiceZyme view
KEGG KEGG entry
MetaCyc metabolic pathway
PRIAM profile
PDB structures RCSB PDB PDBe PDBsum
Gene Ontology AmiGO / EGO

Chloramphenicol acetyltransferase (or CAT) is a bacterial enzyme (EC 2.3.1.28)[1] that detoxifies the antibiotic chloramphenicol and is responsible for chloramphenicol resistance in bacteria.[2] This enzyme covalently attaches an acetyl group from acetyl-CoA to chloramphenicol, which prevents chloramphenicol from binding to ribosomes. A histidine residue, located in the C-terminal section of the enzyme, plays a central role in its catalytic mechanism.

The crystal structure of the type III enzyme from Escherichia coli with chloramphenicol bound has been determined. CAT is a trimer of identical subunits (monomer Mr 25,000) and the trimeric structure is stabilised by a number of hydrogen bonds, some of which result in the extension of a beta-sheet across the subunit interface. Chloramphenicol binds in a deep pocket located at the boundary between adjacent subunits of the trimer, such that the majority of residues forming the binding pocket belong to one subunit while the catalytically essential histidine belongs to the adjacent subunit. His195 is appropriately positioned to act as a general base catalyst in the reaction, and the required tautomeric stabilisation is provided by an unusual interaction with a main-chain carbonyl oxygen.[3]

Application[edit]

CAT is used as a reporter system to measure the level of a promoter or its tissue-specific expression. The CAT assay involves monitoring acetylation of radioactively labeled chloramphenicol on a TLC plate; CAT activity is determined by looking for the acetylated forms of chloramphenicol, which have a significantly increased migration rate as compared to the unacetylated form.[4]

References[edit]

  1. ^ Engel J, Prockop DJ (1991). "The zipper-like folding of collagen triple helices and the effects of mutations that disrupt the zipper". Annu. Rev. Biophys. Biophys. Chem. 20 (1): 137–152. doi:10.1146/annurev.bb.20.060191.001033. PMID 1867713. 
  2. ^ Shaw WV, Packman LC, Burleigh BD, Dell A, Morris HR, Hartley BS (1979). "Primary structure of a chloramphenicol acetyltransferase specified by R plasmids". Nature 282 (5741): 870–2. doi:10.1038/282870a0. PMID 390404. 
  3. ^ Leslie AG (1990). "Refined crystal structure of type III chloramphenicol acetyltransferase at 1.75 A resolution". J. Mol. Biol. 213 (1): 167–186. doi:10.1016/S0022-2836(05)80129-9. PMID 2187098. 
  4. ^ Gorman, CM; Moffat LF, Howard BH (1982). "Recombinant genomes which express chloramphenicol acetyltransferase in mammalian cells". Mol. Cell. Biol. 2 (9): 1044–1051. doi:10.1128/MCB.2.9.1044. Retrieved 15 October 2012. 

This article incorporates text from the public domain Pfam and InterPro IPR001707

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.

Chloramphenicol acetyltransferase Provide feedback

No Pfam abstract.

Internal database links

External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR001707

Chloramphenicol acetyltransferase (CAT) (EC) [PUBMED:1867713] catalyzes the acetyl-CoA dependent acetylation of chloramphenicol (Cm), an antibiotic which inhibits prokaryotic peptidyltransferase activity. Acetylation of Cm by CAT inactivates the antibiotic. A histidine residue, located in the C-terminal section of the enzyme, plays a central role in its catalytic mechanism.

The crystal structure of the type III enzyme from Escherichia coli with chloramphenicol bound has been determined. CAT is a trimer of identical subunits (monomer Mr 25,000) and the trimeric structure is stabilised by a number of hydrogen bonds, some of which result in the extension of a beta-sheet across the subunit interface. Chloramphenicol binds in a deep pocket located at the boundary between adjacent subunits of the trimer, such that the majority of residues forming the binding pocket belong to one subunit while the catalytically essential histidine belongs to the adjacent subunit. His195 is appropriately positioned to act as a general base catalyst in the reaction, and the required tautomeric stabilisation is provided by an unusual interaction with a main-chain carbonyl oxygen [PUBMED:2187098].

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...

Loading domain graphics...

Pfam Clan

This family is a member of clan CoA-acyltrans (CL0149), which contains the following 7 members:

2-oxoacid_dh AATase Carn_acyltransf CAT Condensation Transferase WES_acyltransf

Alignments

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 using the family HMM. We also generate alignments using four representative proteomes (RP) sets, the NCBI sequence database, and our metagenomics sequence database. More...

View options

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.

  Seed
(12)
Full
(768)
Representative proteomes NCBI
(572)
Meta
(473)
RP15
(52)
RP35
(92)
RP55
(122)
RP75
(135)
Jalview View  View  View  View  View  View  View  View 
HTML View  View  View  View  View  View     
PP/heatmap 1 View  View  View  View  View     
Pfam viewer View  View             

1Cannot generate PP/Heatmap alignments for seeds; no PP data available

Key: ✓ available, x not generated, not available.

Format an alignment

  Seed
(12)
Full
(768)
Representative proteomes NCBI
(572)
Meta
(473)
RP15
(52)
RP35
(92)
RP55
(122)
RP75
(135)
Alignment:
Format:
Order:
Sequence:
Gaps:
Download/view:

Download options

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.

  Seed
(12)
Full
(768)
Representative proteomes NCBI
(572)
Meta
(473)
RP15
(52)
RP35
(92)
RP55
(122)
RP75
(135)
Raw Stockholm Download   Download   Download   Download   Download   Download   Download   Download  
Gzipped Download   Download   Download   Download   Download   Download   Download   Download  

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

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 HMMER3.

Pfam alignments:

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'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: Prosite
Previous IDs: none
Type: Domain
Author: Finn RD
Number in seed: 12
Number in full: 768
Average length of the domain: 191.50 aa
Average identity of full alignment: 33 %
Average coverage of the sequence by the domain: 93.28 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 23193494 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 23.5 23.5
Trusted cut-off 24.2 24.3
Noise cut-off 22.9 23.3
Model length: 206
Family (HMM) version: 13
Download: download the raw HMM for this family

Species distribution

Sunburst controls

Show

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...

Loading sunburst data...

Tree controls

Hide

The tree shows the occurrence of this domain across different species. More...

Loading...

Please note: for large trees this can take some time. While the tree is loading, you can safely switch away from this tab but if you browse away from the family page entirely, the tree will not be loaded.

Interactions

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

NO_synthase CAT

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 CAT domain has been found. There are 61 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 seqence.

Loading structure mapping...