- 作者: Luen Hwu; Kuan-Chun Huang; Dow-Tien Chen; Alan Lin
- 作者服務機構: Institutes of Microbiology and Immunology and Genetice, National Yang-Ming University, Taipei, Taiwan, ROC
- 中文摘要: --
- 英文摘要: Based on the tertiary structure of the ribosome-inactivat-ing protein a-sarcin, domains that are responsible forhydrolyzing ribosomes and naked RNA have been dis-sected. In this study, we found that the head-to-tail inter-action between the first amino B-strand and the last car-boxyl B-strand is not involved in catalyzing the hydroly-sis of ribosomes or ribonucleic acids. Instead, a four-strand pleated B-sheet is indispensable for catalyzingboth substrates, suggesting that a-sarcin and ribonu-clease T1 (RNase T1) share a similar catalytic center. Theintegrity of an amino B-hairpin and that of the loop L3 ina-sarcin are crucial for recognizing and hydrolyzing ribo-somes in vitro and in vivo. However, a mutant proteinwithout the (3-hairpin structure, or with a disrupted loopL3, is still capable of digesting ribonucleic acids. Thefunctional involvement of the B-hairpin and the loop L3in the sarcin stem/loop RNA of ribosomes is demon-strated by a docking model, suggesting that the twostructures are in essence naturally designed to distin-guish ribosome-inactivating proteins from RNase T1 toinactivate ribosomes.
- 中文關鍵字: --
- 英文關鍵字: --