Primer initiation and extension by T7 DNA primase
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چکیده
منابع مشابه
Primer initiation and extension by T7 DNA primase.
T7 DNA primase is composed of a catalytic RNA polymerase domain (RPD) and a zinc-binding domain (ZBD) connected by an unstructured linker. The two domains are required to initiate the synthesis of the diribonucleotide pppAC and its extension into a functional primer pppACCC (de novo synthesis), as well as for the extension of exogenous AC diribonucleotides into an ACCC primer (extension synthes...
متن کاملA complex of the bacteriophage T7 primase-helicase and DNA polymerase directs primer utilization.
The lagging strand of the replication fork is initially copied as short Okazaki fragments produced by the coupled activities of two template-dependent enzymes, a primase that synthesizes RNA primers and a DNA polymerase that elongates them. Gene 4 of bacteriophage T7 encodes a bifunctional primase-helicase that assembles into a ring-shaped hexamer with both DNA unwinding and primer synthesis ac...
متن کاملRole of bacteriophage T7 DNA primase in the initiation of DNA strand synthesis.
Bacteriophage T7 DNA primase (gene-4 protein, 66,000 daltons) enables T7 DNA polymerase to initiate the synthesis of DNA chains on single-stranded templates. An initial step in the process of chain initiation is the formation of an oligoribonucleotide primer by T7 primase. The enzyme, in the presence of natural SS DNA, Mg++ (or Mn++), ATP and CTP (or a mixture of all 4 rNTPs), catalyzes the syn...
متن کاملA257T linker region mutant of T7 helicase-primase protein is defective in DNA loading and rescued by T7 DNA polymerase.
The helicase and primase activities of the hexameric ring-shaped T7 gp4 protein reside in two separate domains connected by a linker region. This linker region is part of the subunit interface between monomers, and point mutations in this region have deleterious effects on the helicase functions. One such linker region mutant, A257T, is analogous to the A359T mutant of the homologous human mito...
متن کاملOligomeric structure of bacteriophage T7 DNA primase/helicase proteins.
The oligomeric structure of bacteriophage T7 gene 4 helicase/primase proteins was investigated using protein cross-linking and high pressure gel-filtration chromatography. Studies were carried out with both 4A' and 4B proteins. 4A' is a M64L mutant of 4A which has similar helicase and primase activities as the wild-type mixture of 4A and 4B proteins (Patel, S. S., Rosenberg, A. H., Studier, F. ...
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ژورنال
عنوان ژورنال: The EMBO Journal
سال: 2006
ISSN: 0261-4189,1460-2075
DOI: 10.1038/sj.emboj.7601112