title: Structure of a red fluorescent protein from Zoanthus, zRFP574, reveals a novel chromophore.
abstract: 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 A resolution in space group C222(1). The crystal structure, refined to a crystallographic R factor of 0.203 (R(free) = 0.249), adopts the beta-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 C(alpha) atom to sp(2) 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.
authors.affiliation: Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Science, Moscow, Russia.
authors.forename: Nadezhda
authors.initials: N
authors.lastname: Pletneva
authors.forename: Sergei
authors.initials: S
authors.lastname: Pletnev
authors.forename: Tamara
authors.initials: T
authors.lastname: Tikhonova
authors.forename: Vladimir
authors.initials: V
authors.lastname: Popov
authors.forename: Vladimir
authors.initials: V
authors.lastname: Martynov
authors.forename: Vladimir
authors.initials: V
authors.lastname: Pletnev
mesh_terms: D000818:Animals; D037421:Anthozoa; D001224:Aspartic Acid / Q000737:chemistry; D018360:Crystallography, X-Ray; D005998:Glycine / Q000737:chemistry; D049408:Luminescent Agents / Q000737:chemistry*; D008164:Luminescent Proteins / Q000737:chemistry*; D008958:Models, Molecular; D017433:Protein Structure, Secondary; D021122:Protein Subunits / Q000737:chemistry; D014443:Tyrosine / Q000737:chemistry; D000097573:Red Fluorescent Protein
chemical_list: D001224:Aspartic Acid; D005998:Glycine; D049408:Luminescent Agents; D008164:Luminescent Proteins; D021122:Protein Subunits; D014443:Tyrosine; D000097573:Red Fluorescent Protein