tailieunhanh - Báo cáo khoa học: C-terminal, endoplasmic reticulum-lumenal domain of prosurfactant protein C – structural features and membrane interactions

Surfactant protein C (SP-C) constitutes the transmembrane part of prosurf-actant protein C (proSP-C) and isa-helical in its native state. The C-termi-nal part of proSP-C (CTC) is localized in the endoplasmic reticulum lumen and binds to misfolded (b-strand) SP-C, thereby preventing its aggregation and amyloid fibril formation. | ễFEBS Journal C-terminal endoplasmic reticulum-lumenal domain of prosurfactant protein C - structural features and membrane interactions Cristina Casals1 Hanna Johansson2 Alejandra Saenz1 Magnus Gustafsson2 3 Carlos Alfonso4 Kerstin Nordling2 and Jan Johansson2 1 Department of Biochemistry and Molecular Biology I CIBER Enfermedades Respiratorias Complutense University of Madrid Spain 2 Department of Anatomy Physiology and Biochemistry Swedish University of AgriculturalSciences The BiomedicalCentre Uppsala Sweden 3 Department of MedicalBiochemistry and Biophysics Karolinska Institutet Stockholm Sweden 4 Centro de Investigaciones Biologicas Consejo Superior de Investigaciones Cientificas Madrid Spain Keywords amyloid disease Brichos domain membrane protein protein lipid interactions Correspondence J. Johansson Department of Anatomy Physiology and Biochemistry Swedish University of AgriculturalSciences The BiomedicalCentre 751 23 Uppsala Sweden Fax 46 18 550762 Tel 46 18 4714065 E-mail Received 27 August 2007 revised 6 November 2007 accepted 4 December 2007 doi Surfactant protein C SP-C constitutes the transmembrane part of prosurfactant protein C proSP-C and is a-helical in its native state. The C-termi-nal part of proSP-C CTC is localized in the endoplasmic reticulum lumen and binds to misfolded b-strand SP-C thereby preventing its aggregation and amyloid fibril formation. In this study we investigated the structure of recombinant human CTC and the effects of CTC-membrane interaction on protein structure. CTC forms noncovalent trimers and supratrimeric oligomers. It contains two intrachain disulfide bridges and its secondary structure is significantly affected by urea or heat only after disulfide reduction. The postulated Brichos domain of CTC with homologs found in proteins associated with amyloid and proliferative disease is up to 1000-fold more protected from limited proteolysis than the rest of CTC. The .