Role of the lysine and arginine residues of vitellogenin in high affinity binding to vitellogenin receptors in locust oocyte membranes.

A specific cell surface receptor mediates the endocytosis of the yolk protein vitellogenin (VTG), a lipoglycoprotein, into growing oocytes of the insect Locusta migratoria. The ability of the VTG receptor to recognize VTG was analyzed in binding tests after modification by five lysine-specific and two other reagents. Progressive chemical modification of the lysyl and arginyl residues resulted in reduction or loss of the derivatized VTG to compete for binding to the VTG receptor with unmodified VTG. Although the precise role of the lysine residues in receptor binding remains to be defined we conclude that they are involved in expression of a recognition site interacting with the binding domain of the VTG receptor. Sulfhydryl groups are not involved in the conformation of the recognition site or binding ability of VTG.