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0  structures 293  species 0  interactions 386  sequences 1  architecture

Family: HlyC (PF02794)

Summary: RTX toxin acyltransferase family

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RTX toxin acyltransferase family Provide feedback

Members of this family are enzymes EC:2.3.1.-. involved in fatty acylation of the protoxins (HlyA) at lysine residues, thereby converting them to the active toxin. Acyl-acyl carrier protein (ACP) is the essential acyl donor. This family show a number of conserved residues that are possible candidates for participation in acyl transfer. Site-directed mutagenesis of the single conserved histidine residue in P06736 resulted in complete inactivation of the enzyme [1].

Literature references

  1. Trent MS, Worsham LM, Ernst-Fonberg ML; , Biochemistry 1999;38:3433-3439.: HlyC, the internal protein acyltransferase that activates hemolysin toxin: role of conserved histidine, serine, and cysteine residues in enzymatic activity as probed by chemical modification and site-directed mutagenesis. PUBMED:10079090 EPMC:10079090


External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR003996

Secretion of virulence factors in Gram-negative bacteria involves transportation of the protein across two membranes to reach the cell exterior [PUBMED:1558765]. Four principal exotoxin secretion systems have been described. In the type II and IV secretion systems, toxins are first exported to the periplasm by way of a cleaved N-terminal signal sequence; a second set of proteins is used for extracellular transport (type II), or the C terminus of the exotoxin itself is used (type IV). Type III secretion involves at least 20 molecules that assemble into a needle; effector proteins are then translocated through this without need of a signal sequence. In the Type I system, a complete channel is formed through both membranes, and the secretion signal is carried on the C terminus of the exotoxin.

The RTX (repeats in toxin) family of cytolytic toxins belong to the Type I secretion system, and are important virulence factors in Gram-negative bacteria. As well as the C-terminal signal sequence, several glycine-rich repeats are also found. These are essential for binding calcium, and are critical for the biological activity of the secreted toxins [PUBMED:8800842]. All RTX toxin operons exist in the order rtxCABD, RtxA protein being the structural component of the exotoxin, both RtxB and D being required for its export from the bacterial cell; RtxC is an acyl-carrier-protein-dependent acyl- modification enzyme, required to convert RtxA to its active form [PUBMED:10470043].

Escherichia coli haemolysin (HlyA) is often quoted as the model for RTX toxins. Recent work on its relative rtxC gene product HlyC [PUBMED:9521785] has revealed that it provides the acylation aspect for post-translational modification of two internal lysine residues in the HlyA protein. Other residues, including His23 and two conserved tyrosine residues, also appear to be important [PUBMED:10413532].

Gene Ontology

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

Domain organisation

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Alignments

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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.

  Seed
(29)
Full
(386)
Representative proteomes NCBI
(249)
Meta
(70)
RP15
(7)
RP35
(23)
RP55
(37)
RP75
(46)
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1Cannot generate PP/Heatmap alignments for seeds; no PP data available

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

Format an alignment

  Seed
(29)
Full
(386)
Representative proteomes NCBI
(249)
Meta
(70)
RP15
(7)
RP35
(23)
RP55
(37)
RP75
(46)
Alignment:
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Sequence:
Gaps:
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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.

  Seed
(29)
Full
(386)
Representative proteomes NCBI
(249)
Meta
(70)
RP15
(7)
RP35
(23)
RP55
(37)
RP75
(46)
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

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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.

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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: Pfam-B_1230 (Pfam 6.0)
Previous IDs: none
Type: Family
Author: Bateman A
Number in seed: 29
Number in full: 386
Average length of the domain: 134.70 aa
Average identity of full alignment: 34 %
Average coverage of the sequence by the domain: 84.55 %

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 25.0 25.0
Trusted cut-off 25.4 25.1
Noise cut-off 21.2 24.6
Model length: 134
Family (HMM) version: 11
Download: download the raw HMM for this family

Species distribution

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