Aa. Tulub, SECONDARY STRUCTURE OF TUBULIN ON THE EVI DENCE OF FOURIER-TRANSFORM INFRARED-SPECTROSCOPY INVESTIGATION, Biofizika, 42(6), 1997, pp. 1208-1215
Fourier transform infrared technique is used for identifying secondary
structure of GTP/GDP tubulin in the absorbancy region of its amide-I
band. With this technique the band was initially resolved for 3 main a
nd 4 satellite maxima, subsequently taken as starting values for compu
ter resolution of the band into components of Gaussian line shape. A r
esolution of the spectrum into components was carried out with the FUM
ILI software; the resolution error was 1,5%. Improved maxima positions
for the resolved components of GTP tubulin spectrum are as follows: 1
682,2; 1663,7; 1653,2; 1633,4; 1625,4; 1614,0; 1605,7 cm(-1) each assi
gned to the vibrations of a definite structural type of the protein. T
he main part of the structure, similar to 50%, corresponds to beta-ant
iparallel sheet, the contribution of alpha-coils is about of 25%. GDP
tubulin shows the contribution of beta-antiparallel sheet to be greate
r and the contribution of alpha-coil to be less than in GTP tubulin. T
he difference in the maxima positions of GTP and GDP tubulin spectra d
oes not exceed the value of +/-3 cm(-1).