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The bacteriophage phi29 packaging proteins supercoil the DNA ends.
J Mol Biol 1997; 266(5):901-14JM

Abstract

Bacteriophage phi29 DNA with covalently bound terminal protein (DNA-gp3) and its left and right-end restriction fragments (L and R-DNA-gp3) sedimented faster in sucrose density gradients than their proteinase K-treated counterparts, and the faster sedimentation was both gp3 and Mg2+-dependent. Addition of gp16, the phi29 DNA packaging ATPase, further increased the sedimentation rates of both intact DNA-gp3 and L and R-DNA-gp3 fragments. Thus, DNAs with gp3 were more compact than gp3-free DNA, and gp16 further condensed the DNA-gp3 forms. [35S]gp16 cosedimented with the fast-sedimenting DNA-gp3 fragments, and the putative L-DNA-gp3-gp16 complexes were packaged preferentially into proheads in the defined in vitro system. Lariats of DNA-gp3 and L and R-DNA-gp3 observed by electron microscopy rationalized the sedimentation results, and lariats with multiple loops or coils increased tenfold in a preparation of L-DNA-gp3-gp16 complexes. The rapid sedimentation and the structure of the DNA-gp3-gp16 complexes were consistent with supercoiling of lariat loops, and treatment with topoisomerase I shifted fast-sedimenting complexes toward the uncoiled lariat position in sucrose density gradients. DNA-gp3 has a maturation pathway in which the packaging proteins gp3 and gp16 supercoil the DNA ends, probably as a prerequisite for efficient interaction with the prohead.

Authors+Show Affiliations

Department of Microbiology, University of Minnesota, Minneapolis 55455, USA.No affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

9086269

Citation

Grimes, S, and D Anderson. "The Bacteriophage Phi29 Packaging Proteins Supercoil the DNA Ends." Journal of Molecular Biology, vol. 266, no. 5, 1997, pp. 901-14.
Grimes S, Anderson D. The bacteriophage phi29 packaging proteins supercoil the DNA ends. J Mol Biol. 1997;266(5):901-14.
Grimes, S., & Anderson, D. (1997). The bacteriophage phi29 packaging proteins supercoil the DNA ends. Journal of Molecular Biology, 266(5), pp. 901-14.
Grimes S, Anderson D. The Bacteriophage Phi29 Packaging Proteins Supercoil the DNA Ends. J Mol Biol. 1997 Mar 14;266(5):901-14. PubMed PMID: 9086269.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - The bacteriophage phi29 packaging proteins supercoil the DNA ends. AU - Grimes,S, AU - Anderson,D, PY - 1997/3/14/pubmed PY - 1997/3/14/medline PY - 1997/3/14/entrez SP - 901 EP - 14 JF - Journal of molecular biology JO - J. Mol. Biol. VL - 266 IS - 5 N2 - Bacteriophage phi29 DNA with covalently bound terminal protein (DNA-gp3) and its left and right-end restriction fragments (L and R-DNA-gp3) sedimented faster in sucrose density gradients than their proteinase K-treated counterparts, and the faster sedimentation was both gp3 and Mg2+-dependent. Addition of gp16, the phi29 DNA packaging ATPase, further increased the sedimentation rates of both intact DNA-gp3 and L and R-DNA-gp3 fragments. Thus, DNAs with gp3 were more compact than gp3-free DNA, and gp16 further condensed the DNA-gp3 forms. [35S]gp16 cosedimented with the fast-sedimenting DNA-gp3 fragments, and the putative L-DNA-gp3-gp16 complexes were packaged preferentially into proheads in the defined in vitro system. Lariats of DNA-gp3 and L and R-DNA-gp3 observed by electron microscopy rationalized the sedimentation results, and lariats with multiple loops or coils increased tenfold in a preparation of L-DNA-gp3-gp16 complexes. The rapid sedimentation and the structure of the DNA-gp3-gp16 complexes were consistent with supercoiling of lariat loops, and treatment with topoisomerase I shifted fast-sedimenting complexes toward the uncoiled lariat position in sucrose density gradients. DNA-gp3 has a maturation pathway in which the packaging proteins gp3 and gp16 supercoil the DNA ends, probably as a prerequisite for efficient interaction with the prohead. SN - 0022-2836 UR - https://www.unboundmedicine.com/medline/citation/9086269/The_bacteriophage_phi29_packaging_proteins_supercoil_the_DNA_ends_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0022-2836(96)90843-8 DB - PRIME DP - Unbound Medicine ER -