From Proteopediaproteopedia link
Crystal Structure of FKBP52 C-terminal Domain complex with the C-terminal peptide MEEVD of Hsp90
[FKBP4_HUMAN] Immunophilin protein with PPIase and co-chaperone activities (By similarity). Component of unligated steroid receptors heterocomplexes through interaction with heat-shock protein 90 (HSP90). May play a role in the intracellular trafficking of heterooligomeric forms of steroid hormone receptors between cytoplasm and nuclear compartments (By similarity). The isomerase activity controls neuronal growth cones via regulation of TRPC1 channel opening. Acts also as a regulator of microtubule dynamics by inhibiting MAPT/TAU ability to promote microtubule assembly. May have a protective role against oxidative stress in mitochondria.     [HS90B_HUMAN] Molecular chaperone that promotes the maturation, structural maintenance and proper regulation of specific target proteins involved for instance in cell cycle control and signal transduction. Undergoes a functional cycle that is linked to its ATPase activity. This cycle probably induces conformational changes in the client proteins, thereby causing their activation. Interacts dynamically with various co-chaperones that modulate its substrate recognition, ATPase cycle and chaperone function. 
Publication Abstract from PubMed
FK506-binding protein 52 (FKBP52), which binds FK506 and possesses peptidylprolyl isomerase activity, is an important immunophilin involved in the heterocomplex of steroid receptors with heat-shock protein 90. Here we report the crystal structures of two overlapped fragments [N(1-260) and C(145-459)] of FKBP52 and the complex with a C-terminal pentapeptide from heat-shock protein 90. Based on the structures of these two overlapped fragments, the complete putative structure of FKBP52 can be defined. The structure of FKBP52 is composed of two consecutive FKBP domains, a tetratricopeptide repeat domain and a short helical domain beyond the final tetratricopeptide repeat motif. Key structural differences between FKBP52 and FKBP51, including the relative orientations of the four domains and some important residue substitutions, could account for the differential functions of FKBPs.
3D structure of human FK506-binding protein 52: implications for the assembly of the glucocorticoid receptor/Hsp90/immunophilin heterocomplex.,Wu B, Li P, Liu Y, Lou Z, Ding Y, Shu C, Ye S, Bartlam M, Shen B, Rao Z Proc Natl Acad Sci U S A. 2004 Jun 1;101(22):8348-53. Epub 2004 May 24. PMID:15159550
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.