Hi all, I've limited experience interpreting CD spectra, so I might be missing something, but I've collected CD data for a hydrophobic 15-mer peptide that forms a putative alpha-helix. I get a region of strong negative ellipticity, bottoming out at ~222nm; however, I also get a strong positive peak (of equal magnitude to the 222nm minimum) at ~208nm. This 208 peak is opposite to a textbook alpha-helical spectrum (like it's been inverted).
>From what I've read, short alpha-heical peptides often lack 208nm minima, and >protonated carboxyl groups producce positive ellipticity at this wavelength; >however, apart from the C-terminus, I don't have any carboxyl groups, and the >peptide is in standard PBS buffer to boot. Any suggestions on what might be >causing this odd 208 peak? NOTE: current data isn't below 200nm. Thanks! _________________________________________________________________ Bing brings you health info from trusted sources. http://www.bing.com/search?q=pet+allergy&form=MHEINA&publ=WLHMTAG&crea=TXT_MHEINA_Health_Health_PetAllergy_1x1
