Authors
Jozef Sevcik, Lubica Urbanikova, Peter A Leland, Ronald T Raines
Publication date
2002/12/6
Journal
Journal of Biological Chemistry
Volume
277
Issue
49
Pages
47325-47330
Publisher
American Society for Biochemistry and Molecular Biology
Description
Ribonuclease (RNase) Sa3 is secreted by the Gram-positive bacterium Streptomyces aureofaciens. The enzyme catalyzes the cleavage of RNA on the 3′ side of guanosine residues. Here, x-ray diffraction analysis was used to determine the three-dimensional structure of two distinct crystalline forms of RNase Sa3 to a resolution of 2.0 and 1.7 Å. These two structures are similar to each other as well as to that of a homolog, RNase Sa. All of the key active-site residues of RNase Sa (Asn42, Glu44, Glu57, Arg72, and His88) are located in the putative active site of RNase Sa3. Also herein, RNase Sa3 is shown to be toxic to human erythroleukemia cells in culture. Like onconase, which is an amphibian ribonuclease in Phase III clinical trials as a cancer chemotherapeutic, RNase Sa3 is not inhibited by the cytosolic ribonuclease inhibitor protein. Thus, a prokaryotic ribonuclease can be toxic to mammalian cells.
Total citations
Scholar articles
J Sevcik, L Urbanikova, PA Leland, RT Raines - Journal of Biological Chemistry, 2002