4r3e

Publication Abstract from PubMed

Cwc27 is a spliceosomal cyclophilin-type peptidyl-prolyl cis-trans isomerase (PPIase). Here, the crystal structure of a relatively protease-resistant N-terminal fragment of human Cwc27 containing the PPIase domain was determined at 2.0 A resolution. The fragment exhibits a C-terminal appendix and resides in a reduced state compared with the previous oxidized structure of a similar fragment. By combining multiple sequence alignments spanning the eukaryotic tree of life and secondary-structure prediction, Cwc27 proteins across the entire eukaryotic kingdom were identified. This analysis revealed the specific loss of a crucial active-site residue in higher eukaryotic Cwc27 proteins, suggesting that the protein evolved from a prolyl isomerase to a pure proline binder. Noting a fungus-specific insertion in the PPIase domain, the 1.3 A resolution crystal structure of the PPIase domain of Cwc27 from Chaetomium thermophilum was also determined. Although structurally highly similar in the core domain, the C. thermophilum protein displayed a higher thermal stability than its human counterpart, presumably owing to the combined effect of several amino-acid exchanges that reduce the number of long side chains with strained conformations and create new intramolecular interactions, in particular increased hydrogen-bond networks.

Structure and evolution of the spliceosomal peptidyl-prolyl cis-trans isomerase Cwc27.,Ulrich A, Wahl MC Acta Crystallogr D Biol Crystallogr. 2014 Dec 1;70(Pt 12):3110-23. doi:, 10.1107/S1399004714021695. Epub 2014 Nov 22. PMID:25478830^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.