TY  - JOUR
A1  - Matthies, A.
A1  - Nimtz, M.
A1  - Leimkühler, Silke
T1  - Molybdenum cofactor biosynthesis in humans : Identification of a persulfide group in the rhodanese-like domain of MOCS3 by mass spectrometry
N2  - The human MOCS3 protein contains an N-terminal domain similar to the Escherichia coli MoeB protein and a C- terminal segment displaying similarities to the sulfurtransferase rhodanese. MOCS3 is proposed to catalyze both the adenylation and the subsequent generation of a thiocarboxylate group at the C-terminus of the smaller subunit of molybdopterin (MPT) synthase during Moco biosynthesis in humans. Recent studies have shown that the MOCS3 rhodanese-like domain (MOCS3-RLD) catalyzes the transfer of sulfur from thiosulfate to cyanide and is also able to provide the sulfur for the thiocarboxylation of MOCS2A in a defined in vitro system for the generation of MPT from precursor Z. MOCS3-RLD contains four cysteine residues of which only C412 in the six amino acid active loop is conserved in homologous proteins from other organisms. ESI-MS/MS studies gave direct evidence for the formation of a persulfide group that is exclusively formed on C412. Simultaneous mutagenesis of the remaining three cysteine residues showed that none of them is involved in the sulfur transfer reaction in vitro. A disulfide bridge was identified to be formed between C316 and C324, and possible roles of the three noncatalytic cysteine residues are discussed. By ESI-MS/MS a partially gluconoylated N- terminus of the His(6)-tagged MOCS3-RLD was identified (mass increment of 178 Da) which resulted in a heterogeneity of the protein but did not influence sulfurtransferase activity
Y1  - 2005
UR  - https://publishup.uni-potsdam.de/frontdoor/index/index/docId/13773
SN  - 0006-2960
ER  -