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Biochemistry

Title:		ATR-FTIR study of the structure and orientation of transmembrane domains of the Saccharomyces cerevisiae alpha-mating factor receptor in phospholipids
Author(s):		Ding FX; Xie H; Arshava B; Becker JM; Naider F;
Address:		"Department of Chemistry, The College of Staten Island of the City University of New York, Staten Island, New York 10314, USA"
Journal Title:		Biochemistry
Year:		2001
Volume:		40
Issue:		30
Page Number:		8945 - 8954
DOI:		10.1021/bi010394m
ISSN/ISBN:		0006-2960 (Print) 0006-2960 (Linking)
Abstract:		"The structures of seven synthetic transmembrane domains (TMDs) of the alpha-factor receptor (Ste2p) from Saccharomyces cerevisiae were studied in phospholipid multilayers by transmission Fourier transform infrared (FTIR) and attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopies. Peptide conformation assumed in multilayers depended on the method of sample preparation. Amide proton H/D exchange experiments showed that 60-80% of the NH bonds in these TMDs did not exchange with bulk water in 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) multilayers. FTIR results showed that peptides corresponding to TMDs one, two, and seven were mostly alpha-helical in DMPC multilayers. Peptides corresponding to TMDs three and six assumed predominantly beta-sheet structures, whereas those corresponding to TMDs four and five were a mixture of alpha-helices and beta-sheets. ATR-FTIR showed that in DMPC the alpha-helices of TMDs two and five oriented with tilt angles of 34 degrees and 32 degrees, respectively, with respect to the multilayer normal. Similar results were obtained for six of the transmembrane domains in DMPC/DMPG (4:1) multilayers. In a mixture [POPC/POPE/POPS/PI/ergosterol (30:20:5:20:25)] which mimicked the lipid composition of the S. cerevisiae cell membrane, the percentage of alpha-helical structures found for TMDs one and five increased compared to those in DMPC and DMPC/DMPG (4:1) multilayers, and TMD six exhibited a mixture of beta-sheet ( approximately 60%) and alpha-helical ( approximately 40%) structure. These experiments provide biophysical evidence that peptides representing the seven transmembrane domains in Ste2p assume different structures and tilt angles within a membrane multilayer"
Keywords:		Amides Amino Acid Sequence Cell Membrane/chemistry/metabolism Deuterium Dimyristoylphosphatidylcholine/chemistry/metabolism Lipid Bilayers/chemistry/metabolism Mating Factor Membrane Proteins/*chemistry/metabolism Molecular Mimicry Molecular Sequence Data;
Notes:		"MedlineDing, F X Xie, H Arshava, B Becker, J M Naider, F eng GM22086/GM/NIGMS NIH HHS/ GM22087/GM/NIGMS NIH HHS/ Research Support, U.S. Gov't, P.H.S. 2001/07/27 Biochemistry. 2001 Jul 31; 40(30):8945-54. doi: 10.1021/bi010394m"