MODELING OF THE LECTIN-HOMOLOGY DOMAINS OF THE HUMAN AND MURINE LOW-AFFINITY FC-EPSILON RECEPTOR (FC-EPSILON-RII CD23)/

Models of the lectin-homology domains of the human and murine low-affi nity receptors for IgE (Fc epsilon RII/CD23) were built on the basis o f sequence similarity with rat mannose-binding protein, the structure of which is known. The sites on Fc epsilon RII/CD23 that are possibly involved in the interaction with IgE and with another ligand, CD21/CR2 , are proposed. The models may assist the design of protein engineerin g experiments for the study of the reactivity of these molecules.