The Application of Modern Computational Methods for Investigation of Indole-3-acetic Acid Biosynthesis.

E.A.Zakharova, A.A.Shcherbakov, P.V.Kosterin: The Application of Modern Computational Methods for Investigation of Indole-3-acetic Acid Biosynthesis CSIT 1999 : E/E

Abstract

Computer simulations by quantum chemical methods were applied to qualitatively characterize pathways of bacterial production of indole-3-acetic acid (IAA). A telecommunication search was applied to start the simulation with the initial molecular geometry characteristics taken through the network from the Cambridge Crystal Structure Database. Calculations were done in the MNDO approximation using the quantum chemical methods AM1 and PM3. The NMDO95 program was applied. The standard free energy changes (Delta G0'sum) for the synthesis of tryptophan (Trp) from chorismic acid via anthranilic acid and indole were calculated, as were those for several possible pathways for the synthesis of IAA from Trp, viz. via indole-3-acetamide (IAM), indole-3-pyruvic acid (IPyA), and indole-3-acetonitrile (IAN). The Delta G0'sum for Trp synthesis from chorismic acid was - 402 (- 434) kJ/mol (values in parentheses were calculated by PM3 ). The Delta G0'sum for IAA synthesis from Trp were - 565 (- 548) kJ/mol for the IAN pathway, - 481 (- 506) kJ/mol for the IAM pathway, and - 289 (- 306) kJ/mol for the IPyA pathway. The results indicate that there is a high motive force for Trp synthesis from chorismic acid and for IAA synthesis from Trp, and make it unlikely that anthranilic acid and indole act as precursors to IAA in a Trp-independent pathway.

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Printed Edition

Ch. Freytag and V. Wolfengagen (Eds.): CSIT'99, Proceedings of 1st International Workshop on Computer Science and Information Technologies, January 18-22, 1999, Moscow, Russia. MEPhI Publishing 1999, ISBN 5-7262-0263-5

Electronic Edition