Fluorescence and nucleic acid binding properties of bovine leukemia virus nucleocapsid protein.
We used the intrinsic fluorescence of bovine leukemia virus p12, a nucleocapsid protein with two tryptophan-containing zinc fingers (ZFs), to study its conformation and binding to single-stranded nucleic acids. Spectral emission maxima suggested solvent-exposed tryptophans. A peptide derived from ZF1 had a higher quantum yield and longer average lifetime (tau) than ZF2. BLV p12 tau and rotational correlation time were greater than ZF values, but all de-metallated sequences gave similar results. Apo p12 showed reduced fluorescence intensity, tau and loss of secondary structure. DNA-binding affinity of p12 was in the nanomolar range, and decreased 14-fold after Zn++ ejection. Nucleobase preference of BLV p12 was different from the closely related HTLV-1 but similar to HIV-1 and SIV nucleocapsids, both phylogenetically distant.
Morcock
David R
DR
AIDS Vaccine Program, SAIC Frederick, National Cancer Institute at Frederick, Building 535, 5th floor, P.O. Box B, Frederick, Maryland 21702, USA. morcock@ncifcrf.gov
Katakam
Sudhakar
S
Kane
Bradley P
BP
Casas-Finet
José R
JR
D000818:Animals; D002417:Cattle; D002942:Circular Dichroism; D004277:DNA, Single-Stranded / Q000378:metabolism*; D005333:Fetus / Q000378:metabolism; D006801:Humans; D007668:Kidney / Q000378:metabolism; D001909:Leukemia Virus, Bovine / Q000737:chemistry*; D019590:Nucleocapsid Proteins / Q000378:metabolism*; D011487:Protein Conformation; D013050:Spectrometry, Fluorescence; D014364:Tryptophan / Q000378:metabolism; D016335:Zinc Fingers
D004277:DNA, Single-Stranded; D019590:Nucleocapsid Proteins; D014364:Tryptophan