圓二色譜circulardichroism(cd)-文庫(kù)吧
2025-07-03 18:01 本頁(yè)面
【正文】 x 222 208 192 βsheet 216 195 βturn 220230 (weak) 180190 (strong) 205 polypro II helix 190 210230 weak Random coil 200 212 Far UV CD spectra of polyLLys CD signals for same secondary structure can vary (a bit) with environment Lau, Taneja and Hodges (1984) . 259:1325313261 Ef fect of 50% T FE on a coi le dcoilw avelength in nm200 210 220 230 240MRE3 53 02 52 01 51 050TM3 6 a q u e o u sTM3 6 + TFETFE? But on a coiledcoil breaks down helical dimer to single helices ? Although 2ndry structure same CD changes Ef fect of 50% T FE on a monomeric peptidew avele ng th in nm200 210 220 230 240MRE3 53 02 52 01 51 050p e p tid e in w a te rp e p tid e in 5 0 % T F ETFE? Can see this by looking at the effect of trifluoroethanol (TFE) on a coiledcoil similar to GCN4p1 ? TFE induces helicity in all peptides Best fitting procedures use many different proteins for standard spectra ? There are many different algorithms. ? All rely on using up to 20 CD spectra of proteins of known structure. ? By mixing these together a fit spectra is obtained for an unknown. ? For full details see Dichroweb: the online CD analysis tool ? Can generally get accuracies of for helices, for beta sheet, for turns, and for other structure types (Manavalan amp。 Johnson, 1987, Anal. Biochem. 167, 7685). 估算蛋白質(zhì) a螺旋 含量 僅適合 a含量較高的蛋白質(zhì)！ *Yang算法 Limitations of CD secondary structure analysis ? The simple deconvolution of a CD spectrum into 4 or 5 ponents which do not vary from one protein to another is a gross oversimplification. ? The reference CD spectra corresponding to 100% helix, sheet, turn etc are not directly applicable to proteins which contain
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