Binding of divalent cations is essential for the activity of the organellar peptidasome in Arabidopsis thaliana, AtPreP.
The dual-targeted mitochondrial and chloroplastic zinc metallooligopeptidase from Arabidopsis, AtPreP, functions as a peptidasome that degrades targeting peptides and other small unstructured peptides. In addition to Zn located in the catalytic site, AtPreP also contains two Mg-binding sites. We have investigated the role of Mg-binding using AtPreP variants, in which one or both sites were rendered unable to bind Mg(2+). Our results show that metal binding besides that of the active site is crucial for AtPreP proteolysis, particularly the inner site appears essential for normal proteolytic function. This is also supported by its evolutionary conservation among all plant species of PreP.
Bäckman
Hans G
HG
Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden.
Pessoa
João
J
Eneqvist
Therese
T
Glaser
Elzbieta
E
D000595:Amino Acid Sequence; D000818:Animals; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020134:Catalytic Domain; D002413:Cations, Divalent / Q000378:metabolism*; D018360:Crystallography, X-Ray; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D015388:Organelles / Q000201:enzymology*; D010447:Peptide Hydrolases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017354:Point Mutation; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment
D029681:Arabidopsis Proteins; D002413:Cations, Divalent; D010940:Plant Proteins; D020033:Protein Isoforms; D010447:Peptide Hydrolases; C511107:presequence protease PreP, Arabidopsis