Modelling enzyme-oligonucleotide interactions in barnase

¹ Unité de Conformation des Macromolécules Biologiques, Université Libre de Bruxelles, avenue P Héger, CP 160, B 1050 Bruxelles, Belgium ;
² Laboratoire d’Etudes Dynamiques et Structurales de la Sélectivité VI, Université J Fourier, BP 53F, 38041 Grenoble Cedex, France.

Abstract

We have performed a molecular modelling study of the complex of barnase with 5’3’(ApAp2’3’GMPApAp) ribonucleotide. By computing the electrostatic potential around barnase, we have pointed out that the most highly positive region of barnase, thus the most attractive toward the substrate, extends over the active site. Several additional regions were considered as candidates for binding the other phosphates of the pentanucleotide. Our model, which satisfies the currently known biochemical observations, could be readily tested by site directed mutagenesis experiments.