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Mitsis, P.G., Kowalczykowski, S.C., Lehman, I.R. (1993). A single-stranded DNA binding protein from Drosophila melanogaster: characterization of the heterotrimeric protein and its interaction with single-stranded DNA.  Biochemistry 32(19): 5257--5266.
FlyBase ID
FBrf0057831
Publication Type
Research paper
Abstract

We describe the purification to near homogeneity of a single-stranded DNA binding protein from 0-18-h embryos of Drosophila melanogaster. Drosophila SSB (D-SSB) is a heterotrimer with subunits of molecular weight of 70,000, 30,000, and 8000. It has a Stokes radius of 48.6 +/- 2 A and s20,w = 5.0 +/- 0.2 S. The interaction of D-SSB with ssDNA was examined by the quenching of intrinsic protein fluorescence. The binding site size was determined to be n = 22 +/- 4 nucleotides with a maximum quenching Qm = 35 +/- 3%. Equilibrium titrations indicate that D-SSB binds with low cooperativity, omega = 10-300, and high apparent affinity, K omega = (0.7-5) x 10(7) M-1, at 225 mM NaCl. Sedimentation of D-SSB bound to small oligonucleotides demonstrates that D-SSB does not require protein association for binding. D-SSB stimulates the extent and processivity of DNA synthesis of its cognate DNA polymerase alpha. On the basis of these properties, we conclude that D-SSB is the Drosophila cognate of the human and yeast SSB/RP-A proteins.

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    Language of Publication
    English
    Additional Languages of Abstract
    Parent Publication
    Publication Type
    Journal
    Abbreviation
    Biochemistry
    Title
    Biochemistry
    Publication Year
    1962-
    ISBN/ISSN
    0006-2960
    Data From Reference
    Genes (6)
    Physical Interactions (3)