6mv7

Publication Abstract from PubMed

Ribonuclease 6 (RNase 6) is one of eight catalytically active human pancreatic-type RNases that belong to a superfamily of rapidly evolving enzymes. Like some of its human homologues, RNase 6 exhibits host defense properties such as antiviral and antibacterial activities. Recently solved crystal structures of this enzyme in its nucleotide-free form show the conservation of the prototypical kidney-shaped fold preserved among vertebrate RNases, in addition to revealing the presence of a unique secondary active site. In this study, we determine the structural and conformational properties experienced by RNase 6 upon binding to substrate and product analogues. We present the first crystal structures of RNase 6 bound to a nucleotide ligand (adenosine 5'-monophosphate), in addition to RNase 6 bound to phosphate ions. While the enzyme preserves B2 subsite ligand preferences, our results show a lack of typical B2 subsite interactions normally observed in homologous ligand-bound RNases. A comparison of the dynamical properties of RNase 6 in its apo-, substrate-, and product-bound states highlight the unique dynamical properties experienced on time scales ranging from nano- to milliseconds. Overall, our results confirm the specific evolutionary adaptation of RNase 6 relative to its unique catalytic and biological activities.

Insights into Structural and Dynamical Changes Experienced by Human RNase 6 upon Ligand Binding.,Narayanan C, Bernard DN, Letourneau M, Gagnon J, Gagne D, Bafna K, Calmettes C, Couture JF, Agarwal PK, Doucet N Biochemistry. 2020 Feb 18;59(6):755-765. doi: 10.1021/acs.biochem.9b00888. Epub, 2020 Jan 24. PMID:31909602^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.