engleski

Systematic Ab Initio SCF Conformational Analysis of Indol-3-ylacetic Acid Phytohormone (Auxin): Comparison with Experiment and Molecular Mechanics Calculations

Indol-3-ylacetic acid (IAA) is a plant growth hormone (auxin) which controls a number of physiological functions in higher plants. Molecular recognition approaches based on structure/activity correlations include the conformational properties of the substrate. Thus a detailed ab initio SCF (RHF) conformational analysis of IAA has been performed with the basis sets STO-3G, 3-21G, 4-31G, 6-31G* and 6-311G**. A significant basis set dependence occurs for the two smallest basis sets ; the results obtained with the largest basis sets agree well with experimental gas phase and solid state data. Comparison of the ab initio results with those obtained from MM calculations with MM2(87), MM3, CVFF, and cff91 shows considerable differences: MM calculations are unable to locate two of the four different ab initio conformers.

Ab Initio ; IAA ; Auxin ; molecular modelling

Conference: 35th Annual Sanibel Symposium Location: PONCE LEON CONF CTR, ST AUGUSTINE, FL Date: FEB 25-MAR 04, 1995