2ddd
From Proteopedia
Unique behavior of a histidine responsible for an engineered green-to-red photoconversion process
Structural highlights
FunctionEvolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedKikGR 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. See AlsoReferences
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