Electrostatic potential in aminoacylation by aspartyl-tRNAs synthetase.
Based upon the X-ray structures of complexes between tRNAAsp and aspRS including ATP or Asp-AMP, several electrostatic potentials were calculated by solving the Poisson-Boltzmann equation. The potentials indicate clearly that a Mg2+ ion is essential for binding of ATP and that aspartate is identified electrostatically. The alpha-carboxyl group is forced to contact with the alpha-phosphorus atom of ATP, suggesting its inversion to form an Asp-AMP. When the cognate tRNA is bound to the aspRS:Asp-AMP complex, the 3'-hydroxyl group is located in an electrostatically favorable position to transfer the amino acid as a class II aminoacylation.
Tsunoda
M
M
Faculty of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama, Japan.
Takenaka
A
A
Cavarelli
J
J
Rees
B
B
Thierry
J C
JC
Moras
D
D
D000215:Acylation; D000255:Adenosine Triphosphate / Q000378:metabolism; D001226:Aspartate-tRNA Ligase / Q000737:chemistry / Q000378:metabolism*; D001665:Binding Sites; D008956:Models, Chemical; D015394:Molecular Structure; D012349:RNA, Transfer, Asp / Q000737:chemistry / Q000378:metabolism; D055672:Static Electricity
D012349:RNA, Transfer, Asp; D000255:Adenosine Triphosphate; D001226:Aspartate-tRNA Ligase