3MWR

Crystal structure of ribonuclease A tandem enzymes and their interaction with the cytosolic ribonuclease inhibitor

Summary for 3MWR

• Entry DOI: 10.2210/pdb3mwr/pdb
• Related: 1A2W 1BSR 1R3M 1SRN 3MWQ 3MX8 7RSA
• Descriptor: Ribonuclease pancreatic, LINKER, Ribonuclease pancreatic, SULFATE ION, GLYCEROL, ... (4 entities in total)
• Functional Keywords: ribonuclease a tandem enzyme, sgsgsg-linker, hydrolase
• Biological source: Bos taurus; More
• Cellular location: Secreted: P61823
• Total number of polymer chains: 1
• Total formula weight: 28307.41

Authors

Neumann, P.,Leich, F. (deposition date: 2010-05-06, release date: 2011-02-09, Last modification date: 2024-11-13)

Primary citation

Arnold, U.,Leich, F.,Neumann, P.,Lilie, H.,Ulbrich-Hofmann, R.
Crystal structure of RNase A tandem enzymes and their interaction with the cytosolic ribonuclease inhibitor
Febs J., 278:331-340, 2011

PubMed Abstract: Because of their ability to degrade RNA, RNases are potent cytotoxins. The cytotoxic activity of most members of the RNase A superfamily, however, is abolished by the cytosolic ribonuclease inhibitor (RI). RNase A tandem enzymes, in which two RNase A molecules are artificially connected by a peptide linker, and thus have a pseudodimeric structure, exhibit remarkable cytotoxic activity. In vitro, however, these enzymes are still inhibited by RI. Here, we present the crystal structures of three tandem enzymes with the linker sequences GPPG, SGSGSG, and SGRSGRSG, which allowed us to analyze the mode of binding of RI to the RNase A tandem enzymes. Modeling studies with the crystal structures of the RI-RNase A complex and the SGRSGRSG-RNase A tandem enzyme as templates suggested a 1 : 1 binding stoichiometry for the RI-RNase A tandem enzyme complex, with binding of the RI molecule to the N-terminal RNase A entity. These results were experimentally verified by analytical ultracentrifugation, quantitative electrophoresis, and proteolysis studies with trypsin. As other dimeric RNases, which are comparably cytotoxic, either evade RI binding or potentially even bind two RI molecules, inactivation by RI cannot be the crucial limitation to the cytotoxicity of dimeric RNases.

PubMed: 21134128
DOI: 10.1111/j.1742-4658.2010.07957.x

Experimental method

X-RAY DIFFRACTION (1.85 Å)