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PDBsum entry 3lvc
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Fluorescent protein
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PDB id
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3lvc
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References listed in PDB file
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Key reference
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Title
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Structural evidence for a dehydrated intermediate in green fluorescent protein chromophore biosynthesis.
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Authors
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N.V.Pletneva,
V.Z.Pletnev,
K.A.Lukyanov,
N.G.Gurskaya,
E.A.Goryacheva,
V.I.Martynov,
A.Wlodawer,
Z.Dauter,
S.Pletnev.
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Ref.
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J Biol Chem, 2010,
285,
15978-15984.
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PubMed id
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Abstract
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The acGFPL is the first-identified member of a novel, colorless and
non-fluorescent group of green fluorescent protein (GFP)-like proteins. Its
mutant aceGFP, with Gly replacing the invariant catalytic Glu-222, demonstrates
a relatively fast maturation rate and bright green fluorescence (lambda(ex) =
480 nm, lambda(em) = 505 nm). The reverse G222E single mutation in aceGFP
results in the immature, colorless variant aceGFP-G222E, which undergoes
irreversible photoconversion to a green fluorescent state under UV light
exposure. Here we present a high resolution crystallographic study of aceGFP and
aceGFP-G222E in the immature and UV-photoconverted states. A unique and striking
feature of the colorless aceGFP-G222E structure is the chromophore in the
trapped intermediate state, where cyclization of the protein backbone has
occurred, but Tyr-66 still stays in the native, non-oxidized form, with C(alpha)
and C(beta) atoms in the sp(3) hybridization. This experimentally observed
immature aceGFP-G222E structure, characterized by the non-coplanar arrangement
of the imidazolone and phenolic rings, has been attributed to one of the
intermediate states in the GFP chromophore biosynthesis. The UV irradiation
(lambda = 250-300 nm) of aceGFP-G222E drives the chromophore maturation further
to a green fluorescent state, characterized by the conventional coplanar
bicyclic structure with the oxidized double Tyr-66 C(alpha)=C(beta) bond and the
conjugated system of pi-electrons. Structure-based site-directed mutagenesis has
revealed a critical role of the proximal Tyr-220 in the observed effects. In
particular, an alternative reaction pathway via Tyr-220 rather than conventional
wild type Glu-222 has been proposed for aceGFP maturation.
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