A Raman scattering study of the helix-destabilizing gene-5 protein with adenine-containing nucleotides.
Raman spectra of gp5 and complexes of gp5 with poly(rA) and poly(dA) have been determined and analysed. From a fit of the amide I-band with model spectra it follows that the secondary structure of gp5 contains 52% beta-sheet, 28% undefined conformation and 19% alpha-helix. The band at 1032 cm-1 due to phenylalanine has an anomalous intensity both in the spectra of the complexes and the free protein. This possibly indicates a stacked structure present in the protein. Binding of gp5 to poly(rA) and poly(dA) influences the intensity of bands near 1338 and 1480 cm-1 which are considered to be marker-bands for the phosphate-sugar-base conformer. A change in conformation of the nucleotides is also reflected by vibrations originating in the phosphate- and sugar-residues of the backbone. In the spectrum of complexed poly(rA) the intensity of the conformation sensitive band at 813 cm-1, which is due to the phosphodiester group, is zero. It seems that gp5 forces poly(rA) and poly(dA) to a similar conformation. A marker band for stacking interaction in poly(rA) indicates that stacking interactions in the complex have increased.
Otto
C
C
University of Twente, Enschede, The Netherlands.
de Mul
F F
FF
Harmsen
B J
BJ
Greve
J
J
D003090:Coliphages / Q000032:analysis; D004268:DNA-Binding Proteins / Q000378:metabolism*; D009690:Nucleic Acid Conformation; D011061:Poly A / Q000378:metabolism*; D011485:Protein Binding; D011487:Protein Conformation; D013059:Spectrum Analysis, Raman; D014764:Viral Proteins / Q000378:metabolism*
D004268:DNA-Binding Proteins; D014764:Viral Proteins; D011061:Poly A; C015465:poly(dA)