Interacting Binding Sites of Isoleucyl-tRNA Synthetase from Escherichia coli Studied by Equilibrium Partition.

The binding of tRNA^Ile to isoleucyl-tRNA synthetase in the presence of isoleucine or ATP was investigated using the equilibrium partition method. Isoleucine decreased the affinity of tRNA^Ile for the enzyme by a factor of about 5. For the free standard energy of interaction a value of about 1 kcal/mol (4.2 kJ/mol) was calculated. ATP exhibits qualitatively the same effect as isoleucine. A binding of two molecules isoleucine per molecule of enzyme could not be demonstrated even in the presence of ATP and pyrophosphatase. [ABSTRACT FROM AUTHOR]

Copyright of European Journal of Biochemistry is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)