Three-dimensional structure of ribonuclease Ms*3′-guanylic acid complex at 2.5 Å resolution

AbstractThe crystal structure of ribonuclease Ms*3+-guanylic acid complex has been determined by molecular replacement methods based on the known structure of ribonuclease T1. The pattern of hydrogen-bonds between the enzyme and the guanine base is similar to that discovered by Arni et al. [(1988) J. Biol. Chem. 263, 15358–15368] in the crystal structure of ribonuclease T1*2′-guanylic acid complex. As for the possible general base in the trans-phosphorylation step of the catalysis, 0 c 1 of Glu17 is within the hydrogen-bond distance (2.7 Å) of the 2′-0 of the nucleotide while N c 2 of His14 is significantly more distant (3.4 Å) from the 2′-0