  We present a simple model which allows to investigate equilibrium aspects of
molecular recognition between rigid biomolecules on a generic level. Using a
two-stage approach, which consists of a design and a testing step, the role of
cooperativity and of varying bond strength in molecular recognition is
investigated. Cooperativity is found to enhance selectivity. In complexes which
require a high binding flexibility a small number of strong bonds seems to be
favored compared to a situation with many but weak bonds.
