2ddc

Publication Abstract from PubMed

KikGR is a fluorescent protein engineered to display green-to-red photoconvertibility that is induced by irradiation with ultraviolet or violet light. Similar to Kaede and EosFP, two naturally occurring photoconvertible proteins, KikGR contains a His(62)-Tyr(63)-Gly(64) tripeptide sequence, which forms a green chromophore that can be photoconverted to a red one via formal beta-elimination and subsequent extension of a pi-conjugated system. Using a crystallizable variant of KikGR, we determined the structures of both the green and red state at 1.55 A resolution. The double bond between His(62)-C(alpha) and His(62)-C(beta) in the red chromophore is in a cis configuration, indicating that rotation along the His(62) C(alpha)-C(beta) bond occurs following cleavage of the His(62) N(alpha)-C(alpha) bond. This structural rearrangement provides evidence that the beta-elimination reaction governing the green-to-red photoconversion of KikGR follows an E1 (elimination, unimolecular) mechanism.

The E1 mechanism in photo-induced beta-elimination reactions for green-to-red conversion of fluorescent proteins.,Tsutsui H, Shimizu H, Mizuno H, Nukina N, Furuta T, Miyawaki A Chem Biol. 2009 Nov 25;16(11):1140-7. PMID:19942137^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.