title: Structural and functional heterogeneity of single-stranded DNA-binding proteins from calf thymus.
abstract: A new purification technique for 'single-stranded DNA-binding proteins' from calf thymus permits the demonstration of a considerable heterogeneity within these proteins. Several molecular species are obtained with Mr between 24.10(3) and 30.10(3) and pI values between 6 and 8, showing significant differences with regard to the following functional properties: strength of binding to single-stranded DNA; lowering of melting temperature of poly[d(A-T)]; stimulation of DNA polymerase alpha on a poly[d(A-T)] template. Analysis of trypsin digestion products demonstrates that the different molecular species share extensive primary sequence homology. Experiments with antibodies show that the different molecular species are antigenically related and that a 31 kDa protein present in low amounts in our preparations is very cross-reactive.
mesh_terms: D000818:Animals; D002417:Cattle; D004257:DNA Polymerase II / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000302:isolation & purification* / Q000378:metabolism; D008970:Molecular Weight; D009690:Nucleic Acid Conformation; D011067:Poly dA-dT / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation; D013698:Templates, Genetic; D013950:Thymus Gland / Q000378:metabolism*
chemical_list: D004268:DNA-Binding Proteins; D011067:Poly dA-dT; D004257:DNA Polymerase II