caa a22 4500 397558201 CHVBK 20180308164809.0 cr unu---uuuuu 161202e199603 xx s 000 0 eng 10.1093/oxfordjournals.jbchem.a021276 doi (NATIONALLICENCE)oxford-10.1093/oxfordjournals.jbchem.a021276 Enzymatic Properties of Mutant Forms of RNase Rh from Rhizopus niveus as to Asp51 [Elektronische Daten] [Kazuko Ohgi, Mitsuaki Takeuchi, Masanori Iwama, Masachika Irie] In order to determine the role of Asp51 of RNase Rh from Rhizopus nimus, enzymes with mutations at the 51st position, D51N,D51E,D51Q, D51S,D51T,D51A,and D51K, were prepared, and their enzymatic properties were investigated as to specific activity and base specificity. All the mutant enzymes showed relatively high activity toward poly I and poly C, and markedly reduced activity toward poly A and poly U. In particular, the enzymatic activities toward poly I of D51T and D51S were higher than that of RNase RNAP Rh. Among the mutant enzymes, D51N, D51S, and D51T showed more than ca.30% of the activity of RNase Rh, when RNA, poly I and poly C were used as substrates, respectively. The substitution of Ala, Glu, or Lys at Asp51 is unfavorable for enzymatic activity. Among XpGs (X=A,G,U,or C), D51N, D51S,andD51T showed higher activity toward GpG then CpG. Therefore, Asp51 in RNase Rh plays a critical role in the adenylic acid preference of RNase T2 family enzymes. Our results obtained with a protein engineering technique provide basic insights into the control of the base specificity of RNase Rh. © by the Journal of Biochemistry Regular Papers nationallicence aspartic acid residue nationallicence base non-specific ribonuclease nationallicence mechanism of enzymatic action nationallicence Rhizopus niveus nationallicence ribonuclease nationallicence Ohgi Kazuko Department of Microbiology, Hoshi College of Pharmacy, Ebara 2-4-41, Shinagawa-ku, Tokyo 142 aut Takeuchi Mitsuaki Department of Microbiology, Hoshi College of Pharmacy, Ebara 2-4-41, Shinagawa-ku, Tokyo 142 aut Iwama Masanori Department of Microbiology, Hoshi College of Pharmacy, Ebara 2-4-41, Shinagawa-ku, Tokyo 142 aut Irie Masachika Department of Microbiology, Hoshi College of Pharmacy, Ebara 2-4-41, Shinagawa-ku, Tokyo 142 aut The Journal of Biochemistry Oxford University Press 119/3(1996-03), 548-552 0021-924X 119:3<548 1996 119 jbchem https://doi.org/10.1093/oxfordjournals.jbchem.a021276 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1093/oxfordjournals.jbchem.a021276 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Ohgi Kazuko Department of Microbiology, Hoshi College of Pharmacy, Ebara 2-4-41, Shinagawa-ku, Tokyo 142 aut NATIONALLICENCE 700 1- Takeuchi Mitsuaki Department of Microbiology, Hoshi College of Pharmacy, Ebara 2-4-41, Shinagawa-ku, Tokyo 142 aut NATIONALLICENCE 700 1- Iwama Masanori Department of Microbiology, Hoshi College of Pharmacy, Ebara 2-4-41, Shinagawa-ku, Tokyo 142 aut NATIONALLICENCE 700 1- Irie Masachika Department of Microbiology, Hoshi College of Pharmacy, Ebara 2-4-41, Shinagawa-ku, Tokyo 142 aut NATIONALLICENCE 773 0- The Journal of Biochemistry Oxford University Press 119/3(1996-03), 548-552 0021-924X 119:3<548 1996 119 jbchem Metadata rights reserved CC BY-NC-4.0 http://creativecommons.org/licenses/by-nc/4.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-oxford