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UV resonance Raman study of angiotensin II conformation in nonaqueous environments: Lipid micelles and acetonitrile

✍ Scribed by Janet S. W. Holtz; Igor K. Lednev; Sanford A. Asher


Publisher
Wiley (John Wiley & Sons)
Year
2000
Tongue
English
Weight
244 KB
Volume
57
Category
Article
ISSN
0006-3525

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✦ Synopsis


We used 206.5-nm excited resonance Raman measurements to examine the angiotensin II (AII) secondary structure in H 2 O in the presence of dodecylphosphocholine (DPC) micelles, sodium dodecylsulfate (SDS) monomers and micelles, and in a 70% acetonitrile (ACN-d)-30% water solution. Our AII-SDS titration absorption studies indicate the formation of a 1:2 AII:SDS complex in which two negatively charged SDS molecules attach to the AII positively charged N terminus and to Arg 2 . Our 206.5-nm excited Raman results indicate that the 1:2 AII:SDS complexation increases the AII ␤-turn composition. We also used 228.9-nm Raman excitation to probe the local solvent accessibility of Tyr 4 (AII) in DPC and SDS micelles. Our Tyr (AII) solvent accessibility studies suggest that the Tyr residue is more exposed to the aqueous environment in SDS micelles than in DPC micelles.