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Characterization of an archaeal ubiquitin‐like protein SAMP1
Author(s) -
Hepowit Nathaniel Lantaca,
Miranda Hugo Venicio,
MaupinFurlow Julie
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.782.8
Subject(s) - biochemistry , ubiquitin , biology , deubiquitinating enzyme , archaea , enzyme , microbiology and biotechnology , gene
Small archaeal modifier protein (SAMP1) structurally resembles the eukaryotic ubiquitin (Ub) and bacterial MoaD, sharing with them the β‐grasp fold and C‐terminal GlyGly motif. Our study was aimed to understand the function of SAMP1 using the haloarchaeon Haloferax volcanii as a model system. We demonstrated in vitro that an archaeal homolog of the ubiquitin‐activating enzyme E1 (named ubiquitin‐like activating enzyme of archaea or UbaA) activates SAMP1 in an ATP‐ or GTP‐dependent manner. LC‐MS/MS analysis shows that SAMP1, like Ub, is conjugated to the Lys of its protein substrates by a mechanism requiring UbaA. Cleavage of SAMP1‐conjugates by a JAB1/MPN/MOV34 protease (HvJAMM1) provides evidence that sampylation is reversible. SAMP1 is also found essential for MoCo‐dependent dimethyl sulfoxide reductase activity, suggesting that SAMP1 functions similarly with MoaD in MoCo biosynthesis. Overall, the shared functional similarities of SAMP1 with Ub and MoaD provide a physiological framework in understanding the evolutionary relationship between two divergent biochemical pathways: protein conjugation and sulfur transfer. This work is funded by NIH (ROI GM057498 ) and DOE (DE‐FG02–05ER1560).