Zinc binding by retroviral integrase.

Zinc binding by integrase from Moloney murine leukaemia virus and a protein A fusion protein containing integrase from human immunodeficiency virus type 1 was demonstrated by a zinc blotting technique using 65ZnCl2. Autoradiography revealed a clear band that was absent from the appropriate controls. This band co-migrated with the major band in Coomassie-stained gels and in immunoblots. This binding activity was retained in the presence of competing divalent cations and was sensitive to oxidation. This is the first demonstration of zinc binding by intact retroviral integrase.