Reversible and oriented immobilization of proteins in a functionally active form on solid surfaces is a prerequisite for the investigation of mol. interactions by surface-sensitive techniques. We demonstrate a method generally applicable for the attachment of proteins to oxide surfaces. A nitrilotriacetic acid group serving as a chelator for transition metal ions was covalently bound to the surface via silane chem. Reversible binding of the green fluorescent protein, modified with a hexahistidine extension, was monitored in situ using total internal reflection fluorescence. The assocn. const. and kinetic parameters of the binding process were detd. The reversible, directed immobilization of proteins on surfaces as described here opens new ways for structural investigation of proteins and receptor-ligand interactions. [on SciFinder (R)]