From Proteopediaproteopedia link
The NMR solution structure of the isolated Apo Pin1 WW domain
[PIN1_HUMAN] Essential PPIase that regulates mitosis presumably by interacting with NIMA and attenuating its mitosis-promoting activity. Displays a preference for an acidic residue N-terminal to the isomerized proline bond. Catalyzes pSer/Thr-Pro cis/trans isomerizations. Down-regulates kinase activity of BTK. Can transactivate multiple oncogenes and induce centrosome amplification, chromosome instability and cell transformation. Required for the efficient dephosphorylation and recycling of RAF1 after mitogen activation.  
Publication Abstract from PubMed
The NMR solution structure of the isolated Apo Pin1 WW domain (6-39) reveals that it adopts a twisted three-stranded antiparallel beta-sheet conformation, very similar to the structure exhibited by the crystal of this domain in the context of the two domain Pin1 protein. While the B factors in the apo x-ray crystal structure indicate that loop 1 and loop 2 are conformationally well defined, the solution NMR data suggest that loop 1 is quite flexible, at least in the absence of the ligand. The NMR chemical shift and nuclear Overhauser effect pattern exhibited by the 6-39 Pin1 WW domain has proven to be diagnostic for demonstrating that single site variants of this domain adopt a normally folded structure. Knowledge of this type is critical before embarking on time-consuming kinetic and thermodynamic studies required for a detailed understanding of beta-sheet folding.
NMR solution structure of the isolated Apo Pin1 WW domain: comparison to the x-ray crystal structures of Pin1.,Kowalski JA, Liu K, Kelly JW Biopolymers. 2002 Feb;63(2):111-21. PMID:11786999
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.