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The structure of a far‐red fluorescent protein, AQ143, shows evidence in support of reported red‐shifting chromophore interactions
Author(s) -
Wannier Timothy M.,
Mayo Stephen L.
Publication year - 2014
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1002/pro.2498
Subject(s) - bathochromic shift , chromophore , fluorescence , far red , fluorescent protein , green fluorescent protein , nile red , chemistry , photochemistry , red light , biophysics , biology , optics , biochemistry , physics , botany , gene
Engineering fluorescent proteins (FPs) to emit light at longer wavelengths is a significant focus in the development of the next generation of fluorescent biomarkers, as far‐red light penetrates tissue with minimal absorption, allowing better imaging inside of biological hosts. Structure‐guided design and directed evolution have led to the discovery of red FPs with significant bathochromic shifts to their emission. Here, we present the crystal structure of one of the most bathochromically shifted FPs reported to date, AQ143, a nine‐point mutant of aeCP597, a chromoprotein from Actinia equina . The 2.19 Å resolution structure reveals several important chromophore interactions that contribute to the protein's far‐red emission and shows dual occupancy of the green and red chromophores.