Add time:09/07/2019         Source:sciencedirect.com

In order to elucidate the substrate specificity of alanyl-tRNA synthetase, 5′-O-[N-(l-alanyl)sulfamoyl]adenosine (Ala-SA), an analogue of alanyl-AMP, was chemically synthesized. Its binding ability is similar to that of the substrate based on the inhibitory activity for the aminoacylation of alanyl-tRNA synthetase. Taking advantage of the stable sulfamoyl bond of Ala-SA, compared with the highly labile aminoacyl bond of alanyl-AMP, the molecular conformation of the former inhibitor was studied by X-ray single crystal analysis. Crystal data are as follows: C13H19N7O7S 2H2O, space group C2, a = 39.620(6), b = 5.757(1), c = 20.040(3)Å, β = 117.2(1)°, V = 4065(9)Å3, Z = 8, and final >R = 0.065 for 2785 independent reflections of F02 ≧ 2 σ(F0)2. In the crystal, the molecule is in a zwitterionic state with the terminal amino group protonated and sulfamoyl group deprotonated, and takes an open conformation, where the l-alanine moiety is located far from the adenosine moiety with gauche/trans and trans orientations about the exocyclic C(4′)-C(5′) and C(5′)-O(5′) bonds, respectively. The conformation of the adenosine moiety is anti for the glycosyl bond and C(3′)-endo for the ribose puckering, and alanine is in the usually observed trans region for the ψ torsion angle. The molecular dimensions of the sulfamoyl group are nearly the same as those of the phosphate group. The biological significance of the observed Ala-SA conformation is discussed in relation with the molecular conformation of tyrosyl-AMP complexed with tyrosyl-tRNA synthetase.

We also recommend Trading Suppliers and Manufacturers of 3-SULFAMOYL-L-ALANINE (cas 18625-03-1). Pls Click Website Link as below: cas 18625-03-1 suppliers