Structural basis for dual excitation and photoisomerization of the Aequorea victoria green fluorescent protein.

ABSTRACT: The 2.1-A resolution crystal structure of wild-type green fluorescent protein and comparison of it with the recently determined structure of the Ser-65 --> Thr (S65T) mutant explains the dual wavelength absorption and photoisomerization properties of the wild-type protein. The two absorption maxima are caused by a change in the ionization state of the chromophore. The equilibrium between these states appears to be governed by a hydrogen bond network that permits proton transfer between the chromophore and neighboring side chains. The predominant neutral form of the fluorophore maximally absorbs at 395 nm. It is maintained by the carboxylate of Glu-222 through electrostatic repulsion and hydrogen bonding via a bound water molecule and Ser-205. The ionized form of the fluorophore, absorbing

SUBMITTER: Brejc K 

PROVIDER: S-EPMC20083 | biostudies-literature | 1997 Mar

REPOSITORIES: biostudies-literature