Telomeric and tetraplex DNA binding properties of qTBP42: a homologue of the CArG box binding protein CBF-A.
qTBP42, a rat liver binding protein of telomeric and of guanine-rich single stranded or tetraplex DNA (Sarig, G., Weisman-Shomer, P., Erlitzki, R., and Fry, M. (1997) J. Biol. Chem. 272, 4474-4482), is identified here by its partial amino acid sequence as a homologue of the mouse muscle cell CArG box binding protein CBF-A. Complexes of qTBP42 with single stranded telomeric DNA or with double or single stranded CArG DNA are formed non-cooperatively and have a similar nanomolar-range dissociation constants, Kd. Double stranded telomeric or Plasmid DNA or poly d[(I-C)] are bound by qTBP42 less tightly. Analysis of the binding of tetramolecular quadruplex structures of the IgG switch sequence indicates that one molecule of qTBP42 associates with a single cluster of guanine quartets. The tight binding by qTBP42 of CArG box DNA, telomeric DNA and quadruplex DNA suggests that this protein may bind multiple targets in cellular DNA.
Sarig
G
G
Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Bat Galim, Haifa, Israel.
Weisman-Shomer
P
P
Fry
M
M
D000595:Amino Acid Sequence; D000818:Animals; D018797:Cell Cycle Proteins; D002852:Chromatography, Ion Exchange; D004247:DNA / Q000378:metabolism*; D004277:DNA, Single-Stranded / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B; D006801:Humans; D007231:Infant, Newborn; D007700:Kinetics; D008099:Liver / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D018482:Muscle, Skeletal / Q000378:metabolism; D051381:Rats; D012097:Repressor Proteins / Q000737:chemistry*; D012261:Ribonucleoproteins; D016415:Sequence Alignment; D016615:Telomere / Q000378:metabolism*; D034501:Telomere-Binding Proteins; D014157:Transcription Factors
D018797:Cell Cycle Proteins; D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B; C121363:Hnrnpab protein, rat; D012097:Repressor Proteins; D012261:Ribonucleoproteins; D034501:Telomere-Binding Proteins; D014157:Transcription Factors; C440851:quadruplex telomeric DNA-binding protein 42, rat; C077048:Hnrnpab protein, mouse; D004247:DNA