Interference of GFP incorporation in lambda capsid with phage infectivity. Lambda phages displaying GFP at the N-terminal end of the gpD (GFP-N-λ), at the C-terminal end (GFP-C-λ) or in new positions inside of the gpD protein (GFP-2-λ, GFP-3-λ, GFP-4-λ), were assayed by using anti-gpV antibody-coated ELISA plate and polyclonal anti-λ rabbit antibodies to reveal the bound phage. Phage quantities/well are indicated. Results are expressed as A=A450-A620. Data reported are the average values of assays performed in duplicate. Error bars represent the standard deviation of the mean.