Three-Dimensional Structure of the Immunophilin-like Domain of FKBP59 in Solution^,

Abstract

FKBP59 is a protein usually associated with heat-shock protein hsp90 and steroid receptors. The N-terminal domain of the rabbit liver protein (149 amino acids) has a sequence homology with FKBP12, binds FK506 immunosuppressor, and has a peptidyl-prolyl cis-trans isomerase activity. The three-dimensional structure of this domain (FKBP59-I) was determined using homo- and heteronuclear multidimensional NMR spectroscopy, distance geometry, and molecular dynamics methods. Structure calculations used 1290 interproton distance restraints derived from nuclear Overhauser enhancement measurements, 29 dihedral phi angle restraints, and 92 hydrogen bond restraints. For the final 22 structures, the root mean square distance from the mean atomic coordinates, calculated for well-defined secondary structure fragments, is 0.47 +/- 0.05 and 1.26 +/- 0.15 A for backbone heavy atoms (N, C alpha, C') and for all non-hydrogen atoms, respectively. The global fold contains a twisted six-stranded antiparallel beta-sheet and a short alpha-helix packed on the hydrophobic side of the sheet. The 20 N-terminal and 12 C-terminal amino acids of the domain are disordered. The main-chain structure of FKBP59-I is globally similar to the NMR-derived and X-ray structures of unbound FKBP12. An unusual hydrogen bond interaction between the indole amino proton of Trp 89 and the aromatic cycle of Phe 129 was observed. This gives a large upfield shift (-4.8 ppm) and a significant exchange protection factor. The implications of the present structure determination on the ligand binding of FKBP59 are discussed.

Affinity modulation of small-molecule ligands by borrowing endogenous protein surfaces

“…However, the structures of the FK506-binding domains from both proteins are very similar (19), and it is unlikely that preorganization of the relatively flexible pYEEI peptide is responsible for the observed binding enhancement. Thus, we conclude that when the Fyn SH2 domain binds to the FKpYEEI-FKBP52 complex, the SH2 domain makes additional favorable proteinprotein interactions with FKBP52 that enhance the overall stability of the trimeric complex (Fig.…”

“…SLF is smaller than FK506 and does not project as far from the FKBP protein surface. By using the three-dimensional structures of FKBP12 (15,18), FKBP52 (19), and the Fyn SH2 domain (20), the linkers between the two halves of the bifunctional molecules were designed to bring the FKBP surface into close proximity to the SH2 domain surface. The affinities of FKpYEEI and SLFpYEEI for recombinant FKBP12, FKBP52, and the Fyn SH2 domain were measured by using isothermal titration calorimetry (ITC, Table 1).…”

1H, 13C, and 15N resonance assignments of Fusarium solani pisi cutinase and preliminary features of the structure in solution

“…very recently. in Bncillus circ~rlarts xylanase (Plesniak et al, 1996) and the immunophilin-like domain of FKBP59 (Craescu et al. 1996).…”

Aromatic interactions in homeodomains contribute to the low quantum yield of a conserved, buried tryptophan

“…40 NMR characterization of the FKBP59 immunophilin, which is homologous to FKBP12, demonstrates the presence of a hydrogen bond between the indole nitrogen of Trp 89 and the center of the aromatic ring of Phe 129. 41 The two rings are oriented perpendicularly, with the indole nitrogen proton pointing directly towards the center of the phenylalanine ring. Time-resolved fluorescence measurements on FKBP12 further suggests that the presence of this hydrogen bond correlates with the weak fluorescence of Trp 59.…”