The long-range electrostatic interactions control tRNA-aminoacyl-tRNA synthetase complex formation.
In most cases aminoacyl-tRNA synthetases (aaRSs) are negatively charged, as are the tRNA substrates. It is apparent that there are driving forces that provide a long-range attraction between like charge aaRS and tRNA, and ensure formation of "close encounters." Based on numerical solutions to the nonlinear Poisson-Boltzmann equation, we evaluated the electrostatic potential generated by different aaRSs. The 3D-isopotential surfaces calculated for different aaRSs at 0.01 kT/e contour level reveal the presence of large positive patches-one patch for each tRNA molecule. This is true for classes I and II monomers, dimers, and heterotetramers. The potential maps keep their characteristic features over a wide range of contour levels. The results suggest that nonspecific electrostatic interactions are the driving forces of primary stickiness of aaRSs-tRNA complexes. The long-range attraction in aaRS-tRNA systems is explained by capture of negatively charged tRNA into "blue space area" of the positive potential generated by aaRSs. Localization of tRNA in this area is a prerequisite for overcoming the barrier of Brownian motion.
Tworowski
Dmitry
D
Department of Structural Biology, Weizmann Institute of Science, 76100 Rehovot, Israel.
Safro
Mark
M
D000604:Amino Acyl-tRNA Synthetases / Q000737:chemistry*; D001665:Binding Sites; D016208:Databases, Factual; D008958:Models, Molecular; D009038:Motion; D011487:Protein Conformation; D012346:RNA, Transfer, Amino Acyl / Q000737:chemistry*; D055672:Static Electricity; D013329:Structure-Activity Relationship
D012346:RNA, Transfer, Amino Acyl; D000604:Amino Acyl-tRNA Synthetases