The recently developed method of site-directed Fourier transform infrared dichroism for obtaining orientational constraints of oriented polymers is applied here to the transmembrane domain of the vpu protein from the human immunodeficiency virus type 1 (HIV-1). The infrared spectra of the 31-residue-long vpu peptide reconstituted in lipid vesicles reveal a predominantly alpha-helical structure. The infrared dichroism data of the C-13-labeled peptide yielded a helix tilt beta = (6.5 +/- 1.7)degrees from the membrane normal. The rotational pitch angle omega, defined as zero for a residue located in the direction of the helix tilt, is omega = (283 +/- 11)degrees for the C-13 labels Va(13)/Val(20) and omega = (23 +/- 11)degrees for the C-13 labels Ala(14)/Val(21). A global molecular dynamics search protocol restraining the helix tilt to the experimental value was performed for oligomers of four, five, and six subunits. From 288 structures for each oligomer, a left-handed pentameric coiled coil was obtained, which best fits the experimental data. The structure reveals a pore occluded by Trp residues at the intracellular end of the transmembrane domain.
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Michigan State Univ, Dept Chem, E Lansing, MI 48824 USA
Nantes Univ, UMR 6457,Inst Mines Telecom Atlantique, CNRS,IN2P3, Lab SUBATECH, F-44307 Nantes, FranceMichigan State Univ, Dept Chem, E Lansing, MI 48824 USA
Loganathan, Narasimhan
Kalinichev, Andrey G.
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Nantes Univ, UMR 6457,Inst Mines Telecom Atlantique, CNRS,IN2P3, Lab SUBATECH, F-44307 Nantes, FranceMichigan State Univ, Dept Chem, E Lansing, MI 48824 USA
机构:
Council Sci & Ind Res CSIR Cent Leather Res Inst C, Organ & Bioorgan Chem Lab, Chennai 600020, India
Acad Sci & Innovat Res AcSIR, Ghaziabad 201002, IndiaCouncil Sci & Ind Res CSIR Cent Leather Res Inst C, Organ & Bioorgan Chem Lab, Chennai 600020, India
Unnikrishnan, Anagha C.
Shanmugam, Ganesh
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Council Sci & Ind Res CSIR Cent Leather Res Inst C, Organ & Bioorgan Chem Lab, Chennai 600020, India
CSIR Cent Leather Res Inst, Organ & Bioorgan Chem Lab, Sardar Patel Rd, Chennai 600020, IndiaCouncil Sci & Ind Res CSIR Cent Leather Res Inst C, Organ & Bioorgan Chem Lab, Chennai 600020, India
机构:
Chongqing Univ Sci & Technol, Sch Met Mat Engn, Chongqing 401331, Peoples R ChinaChongqing Univ Sci & Technol, Sch Met Mat Engn, Chongqing 401331, Peoples R China
Qin Yuelin
Liu Hao
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Chongqing Univ Sci & Technol, Sch Met Mat Engn, Chongqing 401331, Peoples R ChinaChongqing Univ Sci & Technol, Sch Met Mat Engn, Chongqing 401331, Peoples R China
Liu Hao
Yang Yanhua
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Chongqing Univ Sci & Technol, Sch Met Mat Engn, Chongqing 401331, Peoples R ChinaChongqing Univ Sci & Technol, Sch Met Mat Engn, Chongqing 401331, Peoples R China