Domain

Phytochelatin synthase, N-terminal catalytic domain (IPR007719)

Short name: PCS_N

Overlapping homologous superfamilies

Domain relationships

None.

Description

Phytochelatins are well known as the heavy metal-detoxifying peptides in higher plants, eukaryotic algae, fungi, nematode and cyanobacteria. Phytochelatin synthase (PCS, also known as glutathione gamma-glutamylcysteinyltransferase; EC:2.3.2.15) is involved in the synthesis of phytochelatins (PC) and homophytochelatins (hPC). 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 [PMID: 18270423]. The C-terminal region displays homology to the functional domains of metallothionein and metallochaperone.

This entry represents the N-terminal catalytic PCS domain, which belongs to the petidase family C83 of the papain superfamily of cysteine proteases, with a structurally conserved "catalytic triad" and oxyanion hole in the active site. It has an overall "crescent" shape with alpha/beta fold containing eight alpha-helices and six beta-strands [PMID: 16339904].

GO terms

Biological Process

GO:0046938 phytochelatin biosynthetic process
GO:0010038 response to metal ion

Molecular Function

GO:0016756 glutathione gamma-glutamylcysteinyltransferase activity
GO:0046872 metal ion binding

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
PROSITE profiles
Pfam