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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1975-5-10
pubmed:abstractText
DNA polymerase III has been purified 4,500-fold from the Escherichis coli mutant, HMS83, which lacks DNA polymerases I and II. When subjected to disc gel electrophoresis, the most purified fraction exhibits a single major protein band from which enzymatic activity may be recovered. Polyacrylamide gel electrophoresis under denaturing conditions produces two protein bands with molecular weights of 140,000 and 40,000. The sedimentation coefficient of the enzyme is 7.0 S, and the Stokes radius is 62 A. Taken together these tow parameters indicate a native molecular weight of 180,000. Purified DNA polymerase III catalyzes the polymerization of nucleotides into DNA when provided with both a DNA template and a complementary primer strand. The newly synthesized DNA is covalently attached to the 3' terminus of the primer strand. Because the extent of polymerization is only 10 to 100 nucleotides, the best substrates are native DNA molecules with small single-stranded regions. The most purified enzyme preparation is devoid of endonuclease activities. In addition to the two exonuclease activities described in the accompanying paper, purified polymerase III also catalyzes pyrophosphorolysis and the exchange of pyrophosphate into deoxynucleoside triphosphates. DNA polymerase III has also been isolated from wild type E. coli containing the other two known DNA polymerases. Futhermore, the enzyme purified from three different polC mutants exhibits altered polymerase III activity, confirming that polC is the structural gene for DNA polymerase III (Gefter, M., Hirota, Y., Kornberb, T., Wechsler, J., and Barnoux, C. (1971) Proc. Natl. Acad. Sci. U. S. A. 68, 3150-3153).
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
25
pubmed:volume
250
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
461-9
pubmed:dateRevised
2009-10-27
pubmed:meshHeading
pubmed:year
1975
pubmed:articleTitle
Deoxyribonucleic acid polymerase III of Escherichia coli. Purification and properties.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.