Structure of a red fluorescent protein from Zoanthus, zRFP574, reveals a novel chromophore

The three-dimensional structure of the red fluorescent protein (RFP) zRFP574 from the button polyp Zoanthus sp. (two dimers per asymmetric unit, 231 x 4 amino acids) has been determined at 2.4 Å resolution in space group C2221. The crystal structure, refined to a crystallographic R factor of 0.203 (Rfree = 0.249), adopts the β-barrel fold composed of 11 strands similar to that of the yellow fluorescent protein zYFP538. The zRFP574 chromophore, originating from the protein sequence Asp66-Tyr67-Gly68, has a two-ring structure typical of GFP-like proteins. The bond geometry of residue 66 shows the strong tendency of the corresponding Cα atom to sp2 hybridization as a consequence of N-acylimine bond formation. The zRFP574 chromophore contains the 65-66 cis-peptide bond characteristic of red fluorescent proteins. The chromophore phenolic ring adopts a cis conformation coplanar with the imidazolinone ring. The crystallographic study has revealed an unexpected chemical feature of the internal chromophore. A decarboxylated side chain of the chromophore-forming residue Asp66 has been observed in the structure. This additional post-translational modification is likely to play a key role in the bathochromic shift of the zRFP574 spectrum. © 2006 International Union of Crystallography - all rights reserved.

Pletneva N, Pletnev S, Tikhonova T, Popov V, Martynov V, Pletnev V

IBCH: 944
Ссылка на статью в журнале: http://scripts.iucr.org/cgi-bin/paper?S0907444906007852
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