Computer modelling of the interaction between human choriogonadotropin and its receptor

Primary structural homology between the hormone binding siteof the LH/CG receptor and the enzyme binding site of chymotrypsininhibitor has been identified. This has led to the applicationof a knowledge-based approach of molecular modelling to describethe interaction of choriogonadotropin (CG) with the LH/CG receptor.A tertiary structural model for the mode of recognition betweenthe hormone and the receptor has been proposed. As in othersuch processes at the molecular level, the recognition betweenCG and its receptor is mediated through non-covalent interactions.The specificity of recognition is achieved by complementarityin van der Waals surfaces, hydrogen bonding and non-polar associations.The model shows nine hydrogen bonds between the hormone andthe receptor involving polar side chains as well as backboneamine and carbonyl groups. A hydropbobic cluster involving sidechain groups at the interface is also important in stabilizationof the intermolecular interactions