Orientation and depth of surfactant protein B C-terminal helix in lung surfactant bilayers

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• 作者：Philippe Bertani^a ; ¹ ; Verica Vidovic^a ; ¹ ; Tran-chin Yang^b ; ¹ ; Jennifer Rendell^b ; Larry M. Gordon^c ; Alan J. Waring^d ; Burkhard Bechinger^a ; Valerie Booth^a ; ^e ; ^{vbooth@mun.ca}
• 关键词：RDS ; Respiratory Distress Syndrome ; ARDS ; Acute Respiratory Distress Syndrome ; SP-B ; Surfactant Protein B ; SDS ; sodium dodecyl sulfate ; BLES ; bovine lipid extract surfactant ; MD ; molecular dynamics ; Fmoc ; O-fluorenylmethyl-oxycarbonyl ; r.h. ; relative humi
• 刊名：Biochimica et Biophysica Acta (BBA)/Biomembranes
• 出版年：2012
• 出版时间：May, 2012
• 年：2012
• 卷：1818
• 期：5
• 页码：1165-1172
• 全文大小：1016 K

文摘

SP-B_CTERM is a cationic amphipathic helical peptide and functional fragment composed of residues 63 to 78 of surfactant protein B (SP-B). Static oriented and magic angle spinning solid state NMR, along with molecular dynamics simulation was used to investigate its structure, orientation, and depth in lipid bilayers of several compositions, namely POPC, DPPC, DPPC/POPC/POPG, and bovine lung surfactant extract (BLES). In all lipid environments the peptide was oriented parallel to the membrane surface. While maintaining this approximately planar orientation, SP-B_CTERM exhibited a flexible topology controlled by subtle variations in lipid composition. SP-B_CTERM-induced lipid realignment and/or conformational changes at the level of the head group were observed using ³¹P solid-state NMR spectroscopy. Measurements of the depth of SP-B_CTERM indicated the peptide center positions ~8 ? more deeply than the phosphate headgroups, a topology that may allow the peptide to promote functional lipid structures without causing micellization upon compression.