Characterization of the human ortholog of Mov34 reveals eight N-terminal residues important for MPN domain stability.
Eukaryotic MPN domain proteins are components of the complexes proteasome lid, COP9-signalosome (CSN), and translation initiation factor 3 (eIF3). The proteasome lid Rpn11 and COP9-signalosome Csn5 subunits, which contain the conserved JAMM motif involved in zinc ion coordination, show catalytic isopeptidase activity. Homology modeling indicates that the MPN domain of Mov34 cannot coordinate a zinc ion in the same manner as catalytically active MPN domains. In this work, we show that the MPN domain of Mov34 is highly resistant to proteolysis and the major product comprises residues 9-186, which includes the conserved MPN domain. Two clones containing the MPN domain region (MPN1-177 and MPN1-186) including the eight N-terminal residues show a less pronounced band in the 220 nm region of the CD, indicating lower alpha-helical content relative to the clones lacking these residues (MPN9-177 and MPN9-186). However, clones lacking residues 1-8 show lower expression levels and thermal stability, indicating that residues 1-8 are required for proper folding and stability of this particular MPN domain.
Alves
Beatriz S C
BS
Center for Structural Molecular Biology, Brazilian Synchrotron Light Laboratory, Campinas SP, Brazil.
Oyama
Sérgio
S
Gozzo
Fábio C
FC
Sanches
Mario
M
Guimarães
Beatriz G
BG
Zanchin
Nilson I T
NI
D048868:Adaptor Proteins, Signal Transducing; D000595:Amino Acid Sequence; D000075686:COP9 Signalosome Complex; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D002942:Circular Dichroism; D039642:Eukaryotic Initiation Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D010447:Peptide Hydrolases / Q000378:metabolism; D011480:Protease Inhibitors / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D040681:Structural Homology, Protein
D048868:Adaptor Proteins, Signal Transducing; C470634:COPS6 protein, human; D002352:Carrier Proteins; D039642:Eukaryotic Initiation Factors; D010446:Peptide Fragments; D011480:Protease Inhibitors; D010447:Peptide Hydrolases; D000075686:COP9 Signalosome Complex