The C-terminal fragment of the ribosomal P protein complexed to trichosanthin reveals the interaction between the ribosome-inactivating protein and the ribosome |
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| Authors: | Priscilla Hiu-Mei Too Meiji Kit-Wan Ma Amanda Nga-Sze Mak Yuen-Ting Wong Christine Kit-Ching Tung Guang Zhu Shannon Wing-Ngor Au Kam-Bo Wong and Pang-Chui Shaw |
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| Institution: | 1.Department of Biochemistry, Centre for Protein Science and Crystallography and Molecular Biotechnology Programme, The Chinese University of Hong Kong, Shatin, N.T. and 2.Department of Biochemistry, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China |
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| Abstract: | Ribosome-inactivating proteins (RIPs) inhibit protein synthesis by enzymatically depurinating a specific adenine residue at the sarcin-ricin loop of the 28S rRNA, which thereby prevents the binding of elongation factors to the GTPase activation centre of the ribosome. Here, we present the 2.2 Å crystal structure of trichosanthin (TCS) complexed to the peptide SDDDMGFGLFD, which corresponds to the conserved C-terminal elongation factor binding domain of the ribosomal P protein. The N-terminal region of this peptide interacts with Lys173, Arg174 and Lys177 in TCS, while the C-terminal region is inserted into a hydrophobic pocket. The interaction with the P protein contributes to the ribosome-inactivating activity of TCS. This 11-mer C-terminal P peptide can be docked with selected important plant and bacterial RIPs, indicating that a similar interaction may also occur with other RIPs. |
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