Formation and characteristics of an unusual lambda-DNA species.
An unusual DNA species, termed as DNA species A, has been isolated and purified from thermal-denatured lambda-DNA Hind III by Sephadex G-200 gel filtration. Our studies indicate that DNA species A is resistant to DNase I digestion and has a higher melting point. The new DNA species showed a lower absorbency at 260 nm, and a lower fluorescence quantum yield after interaction with ethidium bromide (EB) than native double-stranded lambda-DNA. CD spectrum of DNA species A consists of a broad positive band centered at 245 nm and a weak negative band at 220 nm. transmission electron microscope (TEM) visualizations showed that their lengths of DNA species A fell mainly in three regions (300-500 nm, 750-1000 nm and 1500 nm) that corresponded to three fluorescence bands in the EB-stained gels. Their apparent width and height were 65-75 nm and 2.2 nm respectively as observed by images of atomic force microscope (AFM).
Cao
E H
EH
Insitute of Biophysics, Academia Sinica, Beijing, China.
Sun
X G
XG
Bai
C L
CL
Liu
C Q
CQ
He
Y J
YJ
Wang
X W
XW
Fang
Y
Y
D002942:Circular Dichroism; D004247:DNA / Q000737:chemistry* / Q000302:isolation & purification / Q000648:ultrastructure; D018625:Microscopy, Atomic Force; D008854:Microscopy, Electron; D009690:Nucleic Acid Conformation; D013050:Spectrometry, Fluorescence
D004247:DNA