Isoaspartyl dipeptidase activity of plant-type asparaginases.
Recombinant plant-type asparaginases from the cyanobacteria Synechocystis sp. PCC (Pasteur culture collection) 6803 and Anabaena sp. PCC 7120, from Escherichia coli and from the plant Arabidopsis thaliana were expressed in E. coli with either an N-terminal or a C-terminal His tag, and purified. Although each of the four enzymes is encoded by a single gene, their mature forms consist of two protein subunits that are generated by autoproteolytic cleavage of the primary translation products at the Gly-Thr bond within the sequence GTI/VG. The enzymes not only deamidated asparagine but also hydrolysed a range of isoaspartyl dipeptides. As various isoaspartyl peptides are known to arise from proteolytic degradation of post-translationally altered proteins containing isoaspartyl residues, and from depolymerization of the cyanobacterial reserve polymer multi-L-arginyl-poly-L-aspartic acid (cyanophycin), plant-type asparaginases may not only function in asparagine catabolism but also in the final steps of protein and cyanophycin degradation. The properties of these enzymes are compared with those of the sequence-related glycosylasparaginases.
Hejazi
Mahdi
M
Institut für Biologie, Humboldt-Universität zu Berlin, Chausseestr. 117, D-10115 Berlin, Germany.
Piotukh
Kirill
K
Mattow
Jens
J
Deutzmann
Rainer
R
Volkmer-Engert
Rudolf
R
Lockau
Wolfgang
W
D000581:Amidohydrolases / Q000737:chemistry; D000595:Amino Acid Sequence; D017033:Anabaena / Q000201:enzymology; D017360:Arabidopsis / Q000201:enzymology; D001120:Arginine / Q000737:chemistry; D001215:Asparaginase / Q000378:metabolism*; D001216:Asparagine / Q000737:chemistry; D001224:Aspartic Acid / Q000737:chemistry; D001227:Aspartylglucosylaminase / Q000737:chemistry; D001426:Bacterial Proteins; D003001:Cloning, Molecular; D000458:Cyanobacteria / Q000201:enzymology; D004150:Dipeptidases / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000378:metabolism; D005822:Genetic Vectors; D015151:Immunoblotting; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry; D010940:Plant Proteins / Q000737:chemistry; D014176:Protein Biosynthesis; D011499:Protein Processing, Post-Translational; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D001426:Bacterial Proteins; D010455:Peptides; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; C024250:cyanophycin; D001224:Aspartic Acid; D001216:Asparagine; D001120:Arginine; D004150:Dipeptidases; C051396:beta-aspartyl peptidase; D000581:Amidohydrolases; C438834:N-terminal nucleophile hydrolase; D001215:Asparaginase; D001227:Aspartylglucosylaminase