DNA "melting" proteins. II. Effects of bacteriophage T4 gene 32-protein binding on the conformation and stability of nucleic acid structures - PubMed (original) (raw)

. 1976 Nov 25;251(22):7215-28.

PMID: 791945

Free article

DNA "melting" proteins. II. Effects of bacteriophage T4 gene 32-protein binding on the conformation and stability of nucleic acid structures

D E Jensen et al. J Biol Chem. 1976.

Free article

Abstract

Bacteriophage T4-coded gene 32-protein is an essential component of the T4 replication and recombination systems. Alberts and co-workers (Alberts, B.M., Amodio, F.J., Jenkins, M., Gutmann, E.D., and Ferris, F.L. (1968) Cold Spring Harbor Symp. Quant. Biol. 33, 289-305) have shown that the major physiological activity of the protein involves preferential and cooperative binding to single-stranded DNA. In this paper, the physiochemical parameters characterizing this "melting" protein system are quantitatively determined. Boundary sedimentation velocity experiments are used to measure the interaction of gene 32-protein with native DNA. The binding is shown to be non-cooperative and involves an overlapping site size (nh) of approximately 10 nucleotide residues (or approximately 5 nucleotide pairs). In analogy with the ribonuclease results (Jensen, D.E., and von Hippel, P.H. (1976) J. Biol. Chem. 251, 7198-7214), the logarithm of the association constant (Kh) is found to be linerarly related to log [Na+]. The binding of gene 32-protein to denatured (single-stranded) DNA involves appreciable distortion of the polynucleotide backbone from the unliganded conformation; binding totally unstacks the bases of both ribose- and deoxyribose-containing polynucleotides at 10 degrees, and results in a hyperchromic change exceeding that which can be induced by heating. This hyperchromism induced in poly(dA) on binding gene 32-protein under low salt (tight binding) conditions is used to determine a value of nc (the single-stranded DNA site size) of approximately 6.7 nucldotide residues per protein. In addition, gene 32-protein binding to single-stranded polynucleotide induces an unusual circular dichroic spectrum characterized principally by a marked decrease in the magnitude of the positive CD band centered at approximately 265 nm. This spectral change is attributed to significant uncoupling of the transition moments of the vicinal bases of the single-stranded polynucleotide on gene 32-protein binding, in accord with the ultraviolet hyperchromism observed. Binding of gene 32-protein to double helical DNA has virtually no effect on the spectral properties of this conformation...

PubMed Disclaimer

Cited by

NMR characterization of RNA binding property of the DEAD-box RNA helicase DDX3X and its implications for helicase activity.
Toyama Y, Shimada I. Toyama Y, et al. Nat Commun. 2024 Apr 25;15(1):3303. doi: 10.1038/s41467-024-47659-w. Nat Commun. 2024. PMID: 38664397 Free PMC article.
Dynamic structure of T4 gene 32 protein filaments facilitates rapid noncooperative protein dissociation.
Cashen BA, Morse M, Rouzina I, Karpel RL, Williams MC. Cashen BA, et al. Nucleic Acids Res. 2023 Sep 8;51(16):8587-8605. doi: 10.1093/nar/gkad595. Nucleic Acids Res. 2023. PMID: 37449435 Free PMC article.
Characterization of the T4 gp32-ssDNA complex by native, cross-linking, and ultraviolet photodissociation mass spectrometry.
Blevins MS, Walker JN, Schaub JM, Finkelstein IJ, Brodbelt JS. Blevins MS, et al. Chem Sci. 2021 Sep 23;12(41):13764-13776. doi: 10.1039/d1sc02861h. eCollection 2021 Oct 27. Chem Sci. 2021. PMID: 34760161 Free PMC article.
SSB Facilitates Fork-Substrate Discrimination by the PriA DNA Helicase.
Tan HY, Bianco PR. Tan HY, et al. ACS Omega. 2021 Jun 15;6(25):16324-16335. doi: 10.1021/acsomega.1c00722. eCollection 2021 Jun 29. ACS Omega. 2021. PMID: 34235303 Free PMC article.
Mapping DNA conformations and interactions within the binding cleft of bacteriophage T4 single-stranded DNA binding protein (gp32) at single nucleotide resolution.
Camel BR, Jose D, Meze K, Dang A, von Hippel PH. Camel BR, et al. Nucleic Acids Res. 2021 Jan 25;49(2):916-927. doi: 10.1093/nar/gkaa1230. Nucleic Acids Res. 2021. PMID: 33367802 Free PMC article.

DNA "melting" proteins. II. Effects of bacteriophage T4 gene 32-protein binding on the conformation and stability of nucleic acid structures - PubMed (original) (raw)