Fig. 5. Three-dimensional structure model of Fundulus heteroclitus 14-3-3.a. The protein structure is shown from Ser 4 to Asn 234 as a ribbon model with gray loop regions and colored helices. The first 3 amino acids of the amino terminus and the last 13 amino acids of the carboxy terminus are not shown because they are too different from the 14-3-3 proteins that have been used as templates during the modeling process. Helices are labeled (H1–H9). H9 corresponds to the 14-3-3 signature motif 2 (S2). Red helices form the outer coat of the protein while the four green helices (H3, H5, H7, H9) form the amphipathic substrate binding groove. The structural arrangement of the substrate binding groove is highly conserved in 14-3-3.a, suggesting that it binds the same set of phosphorylated proteins as other 14-3-3 proteins despite its overall distinct primary structure.
