Members of the S1-P1 nuclease family are zinc dependent phosphoesterases found in plants, fungi, protozoa and some bacteria. These nucleases have many important roles in organisms, such as specific apoptotic functions, stress response to viroid pathogenesis [1], scavenging for nutrients, or symbiont-host interactions [2]. They are often utilized in biochemistry and biotechnology and have potential medical applications [3]. S1 nuclease from Aspergillus oryzae is a singlestrand specific nuclease with 3′-mononucleotidase activity and 5′-mononucleotides, mononucleosides as well as phosphate ions are its products and at the same time competitive inhibitors.
From previous studies non-specificity of S1 nuclease to nucleobases and its ability to remodel its active site is known [4]. The aim of this work is to analyze the differences in the binding of DNA and RNA in the S1 nuclease active site. Our study is based on two new structures at high resolution of S1 nuclease in complex with uridine and cytidin-5′-monophosphate (products of RNA cleavage) and their comparison with the already known structures of complexes of S1 nuclease with DNA products. Structural data are complemented with biophysical techniques in order to explain observed differences in the activity of S1 nuclease against DNA and RNA.
This work was supported by MEYS CR (LM2015043 CIISB) and by the ERDF fund (CZ.02.1.01/0.0/0.0/16_013/0001776).