title: 1.88 A crystal structure of the C domain of hCyP33: a novel domain of peptidyl-prolyl cis-trans isomerase.
abstract: Cyclophilins (CyPs) are a widespreading protein family in living organisms and possess the activity of peptidyl-prolyl cis-trans isomerase (PPIase), which is inhibited by cyclosporin A (CsA). The human nuclear cyclophilin (hCyP33) is the first protein which was found to contain two RNA binding domains at the amino-terminus and a PPIase domain at the carboxyl-terminus. We isolated the hCyP33 gene from the human hematopoietic stem/progenitor cells and expressed it in Escherichia coli, and determined the crystal structure of the C domain of hCyP33 at 1.88 A resolution. The core structure is a beta-barrel covered by two alpha-helices. Superposition of the structure of the C domain of hCyP33 with the structure of CypA suggests that the C domain contains PPIase active site which binds to CsA. Furthermore, C domain seems to be able to bind with the Gag-encoded capsid (CA) of HIV-1 and may affect the viral replication of HIV-1. A key residue of the active site is changed from Ala-103-CypA to Ser-239-hCyP33, which may affect the PPIase domain/substrates interactions.
authors.affiliation: National Key Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101, PR China.
authors.forename: Tao
authors.initials: T
authors.lastname: Wang
authors.forename: Cai-Hong
authors.initials: CH
authors.lastname: Yun
authors.forename: Shen-Yan
authors.initials: SY
authors.lastname: Gu
authors.forename: Wen-Rui
authors.initials: WR
authors.lastname: Chang
authors.forename: Dong-Cai
authors.initials: DC
authors.lastname: Liang
mesh_terms: D018360:Crystallography, X-Ray; D021983:Cyclophilins / Q000737:chemistry*; D008958:Models, Molecular; D011487:Protein Conformation
chemical_list: D021983:Cyclophilins; C114522:PPIE protein, human