title: Hypothetical protein AF2241 from Archaeoglobus fulgidus adopts a cyclophilin-like fold.
abstract: AF2241 is a hypothetical protein from Archaeoglobus fulgidus and it belongs to the PFam domain of unknown function 369 (DUF369). NMR structural determination reveals that AF2241 adopts a cyclophilin-like fold, with a beta-barrel core composed of eight beta-strands, one alpha-helix, and one 3(10) helix located at each end of the barrel. The protein displays a high structural similarity to TM1367, another member of DUF369 whose structure has been determined recently by X-ray crystallography. Structural similarity search shows that AF2241 also has a high similarity to human cyclophilin A, however, sequence alignment and electrostatic potential analysis reveal that the residues in the PPIase catalytic site of human cyclophilin A are not conserved in AF2241 or TM1367. Instead, a putative active site of AF2241 maps to a negatively charged pocket composed of 9 conserved residues. Our results suggest that although AF2241 adopts the same fold as the human cyclophilin A, it may have distinct biological function.
authors.affiliation: Department of Biochemistry, The University of Western Ontario, London, Ontario, Canada.
authors.forename: Xuanjun
authors.initials: X
authors.lastname: Ai
authors.forename: Lei
authors.initials: L
authors.lastname: Li
authors.forename: Anthony
authors.initials: A
authors.lastname: Semesi
authors.forename: Adelinda
authors.initials: A
authors.lastname: Yee
authors.forename: Cheryl H
authors.initials: CH
authors.lastname: Arrowsmith
authors.forename: Shawn S C
authors.initials: SS
authors.lastname: Li
authors.forename: Wing-Yiu
authors.initials: WY
authors.lastname: Choy
mesh_terms: D000595:Amino Acid Sequence; D019843:Archaeal Proteins / Q000737:chemistry*; D019611:Archaeoglobus fulgidus / Q000378:metabolism*; D001665:Binding Sites; D018360:Crystallography, X-Ray; D021984:Cyclophilin A / Q000737:chemistry*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D040901:Proteomics / Q000379:methods; D017386:Sequence Homology, Amino Acid; D055672:Static Electricity
chemical_list: D019843:Archaeal Proteins; D021984:Cyclophilin A