Quantitative Structure-Activity Relationship (QSAR) study on 22 1H-indole-3-acetic acid derivatives with auxin activity was performed by means of Principal Component Analysis (PCA), Hierarchical Cluster Analysis (HCA), Partial Least Squares Regression (PLS) and Multiple Linear Regression (MLR). Molecular geometry of the auxins was optimized at MMFF94 and ab initio B3LYP 6-31G** levels. Modeling of complexes of some auxin molecules with the auxin binding protein 1 (ABP1) was also carried out. Parsimonius PLS and MLR models for prediction of optimal and half-optimal auxin concentrations for Avena L. Sativa coleoptile elongation were obtained with 15 auxins in the training set. HCA and PCA on data for the half-optimal concentration exhibit auxin clustering with respect to substitutent type and position, biological activity, and the size of the active site pockets of ABP1. Molecular graphics of ABP1 – NAA derivative complexes and of the coordination spheres around NAA (1-naphthalenic acid) hydrogen atoms in the ABP1 – NAA complex agrees well with the chemometrics/QSAR results.Proučavanje kvantitativnih relacija izme|u strukture i auksinske aktivnosti za 22 derivata 1H-indol-3-octene kiseline sprovedeno je pomoću analize glavnih komponenata (PCA), hijerarhijske grozdaste analize (HCA), regresije parcijalnih najmanjih kvadrata (PLS) i višestruke linearne regresije (MLR). Molekularna geometrija auksina optimizirana je na razini MMFF94 i ab initio B3LYP 6-31G** teorije. Izvršeno je i modeliranje kompleksa nekih auksinskih molekula i auksinskoga proteina 1 (ABP1). Zadovoljavajući modeli PLS i MLR za predvi|anje optimalne i polu-optimalne auksinske koncentracije za produljenje koleoptila Avena L. Sativa dobiveni su pomoću test-skupova s 15 auksina. Analize podataka HCA i PCA za polu-optimalnu koncentraciju klasificirale su auksine s obzirom na vrstu i mjesto supstitucije, biološku aktivnost i veličinu d`epova u aktivnom mjestu proteina ABP1. Molekularna grafika kompleksa ABP1–NAA derivati kao i koordinacijskih sfera oko vodikovih atoma u NAA (1-naftalenska kiselina) dobro se sla`e s kemometričkim i QSAR rezultatima
