Title : Molecular characterization of the human Calpha-
formylglycine-generating enzyme
Abstract :
- Calpha-formylglycine (FGly) is the catalytic residue in the active site of sulfatases
- In eukaryotes, it is generated in the endoplasmic reticulum by post-translational modification of a conserved cysteine residue
- The FGly-generating enzyme ( FGE ), performing this modification, is an endoplasmic reticulum-resident enzyme that upon overexpression is secreted
- Recombinant FGE was purified from cells and secretions to homogeneity
- Intracellular FGE contains a high mannose type N-glycan, which is processed to the complex type in secreted FGE
- Secreted FGE shows partial N-terminal trimming up to residue 73 without loosing catalytic activity
- FGE is a calcium-binding protein containing an N-terminal ( residues 86-168 ) and a C-terminal ( residues 178-374 ) protease-resistant domain
- The latter is stabilized by three disulfide bridges arranged in a clamp-like manner, which links the third to the eighth, the fourth to the seventh, and the fifth to the sixth cysteine residue
- The innermost cysteine pair is partially reduced
- The first two cysteine residues are located in the sequence preceding the N-terminal protease-resistant domain
- They can form intramolecular or intermolecular disulfide bonds, the latter stabilizing homodimers
- The C-terminal domain comprises the substrate binding site , as evidenced by yeast two-hybrid interaction assays and photocross-linking of a substrate peptide to proline 182
- Peptides derived from all known human sulfatases served as substrates for purified FGE indicating that FGE is sufficient to modify all sulfatases of the same species
Output (sent_index, trigger,
protein,
sugar,
site):
- 5. contains, , Intracellular FGE, a high mannose type N-glycan, -
- 5. type, , FGE, type, -
Output(Part-Of) (sent_index,
protein,
site):
- 10. -, cysteine residues
- 10. N-terminal protease, domain
- 7. FGE, domain
- 7. protease, domain
- 7. protein, domain
*Output_Site_Fusion* (sent_index,
protein,
sugar,
site):