The existence of unique B structures in polynucleotides with alternating purine-pyrimidine sequences.
The infrared spectra of the sodium salts of calf-thymus DNA, poly(dA-dC).poly(dG-dT), poly(dA-dT) and poly(dG-dC) were measured for the samples as highly hydrated, nonoriented gels. The bands from the sugar-phosphate vibrational modes show that poly(dG-dC) assumes a B-family structure which is different from the B structures of the other samples. Poly(dG-dC) most likely assumes a wrinkled B structure. The other samples retain a smooth B structure. An alternating purine-pyrimidine sequence is not a sufficient condition for the formation of wrinkled B structure in a polynucleotide.
Loprete
D M
DM
Department of Biochemistry and Biophysics, University of Rhode Island, Kingston 02881.
Hartman
K A
KA
D004247:DNA / Q000737:chemistry*; D009690:Nucleic Acid Conformation; D011067:Poly dA-dT / Q000737:chemistry*; D011089:Polydeoxyribonucleotides / Q000737:chemistry*; D013055:Spectrophotometry, Infrared
D011089:Polydeoxyribonucleotides; D011067:Poly dA-dT; C019530:poly(dC-dG); C028333:poly(d(A-C).d(G-T)); D004247:DNA