title: Effect of the replacement of aspartic acid/glutamic acid residues with asparagine/glutamine residues in RNase He1 from Hericium erinaceus on inhibition of human leukemia cell line proliferation.
abstract: RNase He1 from Hericium erinaceus, a member of the RNase T1 family, has high identity with RNase Po1 from Pleurotus ostreatus with complete conservation of the catalytic sequence. However, the optimal pH for RNase He1 activity is lower than that of RNase Po1, and the enzyme shows little inhibition of human tumor cell proliferation. Hence, to investigate the potential antitumor activity of recombinant RNase He1 and to possibly enhance its optimum pH, we generated RNase He1 mutants by replacing 12 Asn/Gln residues with Asp/Glu residues; the amino acid sequence of RNase Po1 was taken as reference. These mutants were then expressed in Escherichia coli. Using site-directed mutagenesis, we successfully modified the optimal pH for enzyme activity and generated a recombinant RNase He1 that inhibited the proliferation of cells in the human leukemia cell line. These properties are extremely important in the production of anticancer biologics that are based on RNase activity.
authors.affiliation: a Department of Microbiology, School of Pharmacy , Nihon University , Chiba , Japan.
authors.forename: Hiroko
authors.initials: H
authors.lastname: Kobayashi
authors.forename: Naomi
authors.initials: N
authors.lastname: Motoyoshi
authors.forename: Tadashi
authors.initials: T
authors.lastname: Itagaki
authors.forename: Mamoru
authors.initials: M
authors.lastname: Suzuki
authors.forename: Norio
authors.initials: N
authors.lastname: Inokuchi
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000970:Antineoplastic Agents / Q000737:chemistry* / Q000494:pharmacology*; D001216:Asparagine; D001224:Aspartic Acid; D001487:Basidiomycota / Q000201:enzymology*; D049109:Cell Proliferation / Q000187:drug effects; D018698:Glutamic Acid; D005973:Glutamine; D018922:HL-60 Cells; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007938:Leukemia / Q000473:pathology*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D011487:Protein Conformation; D012260:Ribonucleases / Q000737:chemistry* / Q000235:genetics / Q000494:pharmacology*; D013329:Structure-Activity Relationship
chemical_list: D000970:Antineoplastic Agents; D005973:Glutamine; D001224:Aspartic Acid; D018698:Glutamic Acid; D001216:Asparagine; D012260:Ribonucleases
keywords: Hericium erinaceus; RNase T1 family RNase; inhibition of cell proliferation; site-directed mutant