Secondary-structure analysis of proteins by vacuum-ultraviolet circular dichroism spectroscopy.
The vacuum ultraviolet circular dichroism (VUVCD) spectra of 15 globular proteins (myoglobin, hemoglobin, human serum albumin, cytochrome c, peroxidase, alpha-lactalbumin, lysozyme, ovalbumin, ribonuclease A, beta-lactoglobulin, pepsin, trypsinogen, alpha-chymotrypsinogen, soybean trypsin inhibitor, and concanavalin A) were measured in aqueous solutions at 25 degrees C in the wavelength region from 260 to 160 nm under a high vacuum, using a synchrotron-radiation VUVCD spectrophotometer. The VUVCD spectra below 190 nm revealed some characteristic bands corresponding to different secondary structures. The contents of alpha-helices, beta-strands, turns, and unordered structures were estimated using the SELCON3 program with VUVCD spectra data on the 15 proteins. Prediction of the secondary-structure contents was greatly improved by extending the circular dichroism spectra to 165 nm. The numbers of alpha-helix and beta-strand segments calculated from the distorted alpha-helix and beta-strand contents did not differ greatly from those obtained from X-ray crystal structures. These results demonstrate that synchrotron-radiation VUVCD spectroscopy is a powerful tool for analyzing the secondary structures of proteins.
Matsuo
Koichi
K
Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526.
Yonehara
Ryuta
R
Gekko
Kunihiko
K
D002942:Circular Dichroism / Q000295:instrumentation / Q000379:methods*; D018360:Crystallography, X-Ray; D017433:Protein Structure, Secondary; D011506:Proteins / Q000737:chemistry*; D012984:Software; D013056:Spectrophotometry, Ultraviolet / Q000295:instrumentation / Q000379:methods*; D017356:Synchrotrons
D011506:Proteins