Summary: Phytochelatin synthase
Phytochelatin synthase Provide feedback
Phytochelatin synthase is the enzyme responsible for the synthesis of heavy-metal-binding peptides (phytochelatins) from glutathione and related thiols . The crystal structure of a member of this family shows it to possess a papain fold . The enzyme catalyses the deglycination of a GSH donor molecule . The enzyme contains a catalytic triad of cysteine, histidine and aspartate residues.
Vivares D, Arnoux P, Pignol D; , Proc Natl Acad Sci U S A. 2005;102:18848-18853.: A papain-like enzyme at work: native and acyl-enzyme intermediate structures in phytochelatin synthesis. PUBMED:16339904 EPMC:16339904
External database links
This tab holds annotation information from the InterPro database.
InterPro entry IPR007719
This entry represents plant phytochelatin synthases (also known as glutathione gamma-glutamylcysteinyltransferase; EC), which is involved in the synthesis of phytochelatins (PC) and homophytochelatins (hPC), the heavy-metal-binding peptides of plants. This enzyme is required for detoxification of heavy metals such as cadmium and arsenate. The N-terminal region of phytochelatin synthase contains the active site, as well as four highly conserved cysteine residues that appear to play an important role in heavy-metal-induced phytochelatin catalysis. The C-terminal region is rich in cysteines, and may act as a metal sensor, whereby the Cys residues bind cadmium ions to bring them into closer proximity and transferring them to the activation site in the N-terminal catalytic domain [PUBMED:18270423]. The C-terminal region displays homology to the functional domains of metallothionein and metallochaperone.
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|Molecular function||metal ion binding (GO:0046872)|
|glutathione gamma-glutamylcysteinyltransferase activity (GO:0016756)|
|Biological process||phytochelatin biosynthetic process (GO:0046938)|
|response to metal ion (GO:0010038)|
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Curation and family details
|Seed source:||Pfam-B_9299 (release 7.6)|
|Author:||Wood V, Rawlings ND|
|Number in seed:||20|
|Number in full:||280|
|Average length of the domain:||197.80 aa|
|Average identity of full alignment:||39 %|
|Average coverage of the sequence by the domain:||55.01 %|
|HMM build commands:||
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 23193494 -E 1000 --cpu 4 HMM pfamseq
|Family (HMM) version:||9|
|Download:||download the raw HMM for this family|
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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 Phytochelatin domain has been found. There are 4 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.
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