A detailed binding study of a commonly used herbicide Chlorsulfuron is performed on a naturally occurring plant (and weed) AHAS enzyme together with a mutated form. It is known that a multitude of point mutations in this enzyme can lead to resistance from many different herbicides, and the amino acid substitution P197S is considered in Soybean AHAS. The work shows that resistance to CS is obtained after this substitution, by examining the binding statistically of CS, and is quantified to be in the x20 range or more as far as dose amount to have an effect.