TY - JOUR
T1 - Raman Spectroscopy of Mercury(II) Binding to Two Filamentous Viruses
T2 - Ff (fd, M13, fl) and Pf1*
AU - Day, Loren A.
AU - Casadevall, Arturo
AU - Prescott, Betty
AU - Thomas, George J.
PY - 1988/1/1
Y1 - 1988/1/1
N2 - Ff and Pfl are filamentous bacteriophages. Each contains, in a central core region surrounded by protein, a circular single-stranded DNA molecule, and it is known that the DNA bases are sites of Hg(II) binding. In the present study, Raman spectra were obtained for the two viruses in the presence of increasing amounts of Hg(II), with ratios (m) of Hg(II) added per nucleotide residue in the range 0 < m < 2.0. Hg(II) binding to the viruses induces Raman intensity changes in previously assigned Raman lines of viral DNA, demonstrating metal binding to the DNA bases, but also in many lines assigned to protein. The overall structures of the viruses do not change with Hg(II) binding, and the Raman spectra indicate little, if any, change in protein secondary structure. Changes in certain protein Raman lines induced by Hg(II) binding to the DNA for low values of m are attributed to altered interactions between solvent and protein side chains, aliphatic groups being the most affected. The nature of such changes for both viruses suggests DNA-protein linkage. In Pfl, lines assigned to ring vibrations of all four bases are perturbed upon initial addition of Hg(II) to m = 0.25. In Ff, however, lines assigned to base ring vibrations are not perturbed until m ≥ 0.5. The results provide additional evidence for fundamentally different DNA structures in Ff and Pf1.
AB - Ff and Pfl are filamentous bacteriophages. Each contains, in a central core region surrounded by protein, a circular single-stranded DNA molecule, and it is known that the DNA bases are sites of Hg(II) binding. In the present study, Raman spectra were obtained for the two viruses in the presence of increasing amounts of Hg(II), with ratios (m) of Hg(II) added per nucleotide residue in the range 0 < m < 2.0. Hg(II) binding to the viruses induces Raman intensity changes in previously assigned Raman lines of viral DNA, demonstrating metal binding to the DNA bases, but also in many lines assigned to protein. The overall structures of the viruses do not change with Hg(II) binding, and the Raman spectra indicate little, if any, change in protein secondary structure. Changes in certain protein Raman lines induced by Hg(II) binding to the DNA for low values of m are attributed to altered interactions between solvent and protein side chains, aliphatic groups being the most affected. The nature of such changes for both viruses suggests DNA-protein linkage. In Pfl, lines assigned to ring vibrations of all four bases are perturbed upon initial addition of Hg(II) to m = 0.25. In Ff, however, lines assigned to base ring vibrations are not perturbed until m ≥ 0.5. The results provide additional evidence for fundamentally different DNA structures in Ff and Pf1.
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U2 - 10.1021/bi00402a032
DO - 10.1021/bi00402a032
M3 - Article
C2 - 3280025
AN - SCOPUS:0024297501
SN - 0006-2960
VL - 27
SP - 706
EP - 711
JO - Biochemistry
JF - Biochemistry
IS - 2
ER -