The crystal structure of human WD40 repeat‐containing peptidylprolyl isomerase (PPWD1)

Abstract

Cyclophilins comprise one of the three classes of peptidylprolyl isomerases found in all eukaryotic and prokaryotic organisms, as well as viruses. Many of the 17 annotated human cyclophilins contain the catalytic domain in tandem with other domains, and many of the specific functions of a particular cyclophilin or its associated domains remain unknown. The structure of the isomerase domain from a spliceosome‐associated cyclophilin, PPWD1 (peptidylprolyl isomerase containing WD40 repeat), has been solved to 1.65 Å. In the crystal, the N‐terminus of one isomerase domain is bound in the active site of a neighboring isomerase molecule in a manner analogous to substrate. NMR solution studies show that this sequence binds to the active site of the cyclophilin, but cannot be turned over by the enzyme. A pseudo‐substrate immediately N‐terminal to the cyclophilin domain in PPWD1 could have wider implications for the function of this cyclophilin in the spliceosome, where it is located in human cells.

Structural and Biochemical Characterization of the Human Cyclophilin Family of Peptidyl-Prolyl Isomerases

“…Because of the inherent thermal stability characteristics of PPID and RanBP2, this technique was unable to distinguish between apo and cyclosporin-bound forms of those domains. However, data were collected for the remaining 13 isoforms, and binding to CsA, CsC, or CsD was noted for six isoforms published previously (PPIA, PPIB, PPIC, PPIE, PPIL1, and PPWD1) [20],[27]–[30],[32]. In addition, binding of CsA or derivatives was seen for PPIF, PPIG, PPIH, and NKTR.…”

Nuclear cyclophilins affect spliceosome assembly and function in vitro

“…All of the cyclophilin expression constructs used in the current study have been previously published, along with detailed expression and purification protocols [15,18]. To summarize, expression constructs for all cyclophilins used in the current study were cloned using cDNA from the Mammalian Gene Collection (accession numbers follow: PPIA – BC003026, PPIE – BC008451, PPIG – BC001555, PPIH – BC003412, PPIL1 – BC003048, PPIL2 – BC000022, PPIL3 – BC007693, PPWD1 – BC015385, CWC27 – BC012117).…”

“…Most cyclophilins are peptidyl-prolyl isomerases (PPIs), with the characteristic enzymatic activity of interconverting cis - and trans -isomers of proline on model peptide substrates in vitro [15–17]. The proteins are well characterized in terms of the structure of their PPI domains, their isomerase activity and high-affinity interaction with the drug cyclosporine, which directly blocks proline binding to the active site [15,18–21]. Point mutations that abrogate both cyclosporine binding and isomerase activity have been identified [15,22,23], but even with this knowledge it has not been a straightforward process to identify endogenous targets or to unambiguously identify their cellular functions.…”

Localization of sporadic neuroendocrine tumors by gene expression analysis of their metastases

“…The CD302 protein is a C-type lectin receptor which is involved in cell adhesion and migration, as well as in endocytosis and phagocytosis [59][60][61]. The PPWD1 gene and its encoding protein peptidylprolyl isomerase containing WD40 repeat is described in just one publication [62]. ABHD14B is almost unknown and no publication could be found.…”