CATH Classification

Domain Context

CATH Clusters

Superfamily Type I PLP-dependent aspartate aminotransferase-like (Major domain)
Functional Family Cysteine desulfurase IscS, mitochondrial

Enzyme Information
Selenocysteine lyase.
based on mapping to UniProt P77444
L-selenocysteine + reduced acceptor = selenide + L-alanine + acceptor.
-!- Dithiothreitol or 2-mercaptoethanol can act as the reducing agent in the reaction. -!- The enzyme from animals does not act on cysteine, serine or chloroalanine, while the enzyme from bacteria shows activity with cysteine (cf. EC
Cysteine desulfurase.
based on mapping to UniProt P77444
L-cysteine + acceptor = L-alanine + S-sulfanyl-acceptor.
-!- The sulfur from free L-cysteine is first transferred to a cysteine residue in the active site, and then passed on to various other acceptors. -!- The enzyme is involved in the biosynthesis of iron-sulfur clusters, thio-nucleosides in tRNA, thiamine, biotin, lipoate and pyranopterin (molybdopterin). -!- In Azotobacter vinelandii, this sulfur provides the inorganic sulfide required for nitrogenous metallocluster formation.

UniProtKB Entries (1)

Escherichia coli K-12
Cysteine desulfurase

PDB Structure

PDB 1I29
External Links
Organism Escherichia
Primary Citation
Structure of external aldimine of Escherichia coli CsdB, an IscS/NifS homolog: implications for its specificity toward selenocysteine.
Mihara, H., Fujii, T., Kato, S., Kurihara, T., Hata, Y., Esaki, N.