Structural symmetry of the extracellular domain of the Cytokine/Growth hormone/Prolactin receptor family and Interferon receptors revealed by Hydrophobic Cluster Analysis

Abstract

Sequence comparison based on Hydrophobic Cluster Analysis procedures shows that the extracellular ≈ 200 amino acids domains of cytokines receptors belonging to the Cytokine/Growth hormone/Prolactin receptor family and to the Interferon one are organized in two homologous subdomains. Further, comparison of the subdomains of 32 independent sequences and of a lot of already recognized homologous domains with data bases could lead to the hypothesis that these ≈ 100 amino acids subdomains could possess the overall fold of the constant immunoglobulin domains and so could belong to the immunoglobulin superfamily.