The 2.1 Å Crystal Structure of copGFP, a Representative Member of the Copepod Clade Within the Green Fluorescent Protein Superfamily
The green fluorescent protein (avGFP), its variants, and the closely related GFP-like proteins are characterized structurally by a cyclic tri-peptide chromophore located centrally within a conserved β-can fold. Traditionally, these GFP family members have been isolated from the Cnidaria although rec...
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Published in | Journal of molecular biology Vol. 359; no. 4; pp. 890 - 900 |
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Main Authors | , , , , , , , |
Format | Journal Article |
Language | English |
Published |
Elsevier Ltd
01.06.2006
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Subjects | |
Online Access | Get full text |
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Summary: | The green fluorescent protein (avGFP), its variants, and the closely related GFP-like proteins are characterized structurally by a cyclic tri-peptide chromophore located centrally within a conserved β-can fold. Traditionally, these GFP family members have been isolated from the Cnidaria although recently, distantly related GFP-like proteins from the Bilateria, a sister group of the Cnidaria have been described, although no representative structure from this phylum has been reported to date. We have determined to 2.1
Å resolution the crystal structure of copGFP, a representative GFP-like protein from a copepod, a member of the Bilateria. The structure of copGFP revealed that, despite sharing only 19% sequence identity with GFP, the tri-peptide chromophore (Gly57-Tyr58-Gly59) of copGFP adopted a
cis coplanar conformation within the conserved β-can fold. However, the immediate environment surrounding the chromophore of copGFP was markedly atypical when compared to other members of the GFP-superfamily, with a large network of bulky residues observed to surround the chromophore. Arg87 and Glu222 (GFP numbering 96 and 222), the only two residues conserved between copGFP, GFP and GFP-like proteins are involved in autocatalytic genesis of the chromophore. Accordingly, the copGFP structure provides an alternative platform for the development of a new suite of fluorescent protein tools. Moreover, the structure suggests that the autocatalytic genesis of the chromophore is remarkably tolerant to a high degree of sequence and structural variation within the β-can fold of the GFP superfamily. |
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ISSN: | 0022-2836 1089-8638 |
DOI: | 10.1016/j.jmb.2006.04.002 |