TY - JOUR
T1 - A β-like DNA polymerase from the mitochondrion of the trypanosomatid Crithidia fasciculata
AU - Torri, Al F.
AU - Kunkel, Thomas A.
AU - Englund, Paul T.
N1 - Copyright:
Copyright 2005 Elsevier B.V., All rights reserved.
PY - 1994/3/18
Y1 - 1994/3/18
N2 - The mitochondrial DNA in Crithidia fasciculata, a trypanosomatid parasite, is known as kinetoplast DNA. Kinetoplast DNA has a very unusual structure, consisting of several thousand minicircles and a few dozen maxicircles, all topologically interlocked into a giant network. There is one network within each cell's single mitochondrion. We previously purified a 43-kDa DNA polymerase from C. fasciculata mitochondria (Torri, A. F., and Englund, P. T. (1992) J. Biol. Chem. 267, 4786-4792). This enzyme has properties very different from those of a DNA polymerase γ, the conventional mitochondrial polymerase. In addition to its small size, it is nonprocessive, has no detectable exonuclease activity, and has very low fidelity. In all of these respects, the polymerase resembles a DNA polymerase β, a gap-filling enzyme thought to function in DNA repair in the nucleus of other eukaryotes. We speculate that this enzyme may have been specially imported into the C. fasciculata mitochondrion to repair the many gaps found in minicircles following their replication. This is the first example of a β-like polymerase from the mitochondrion of any eukaryote.
AB - The mitochondrial DNA in Crithidia fasciculata, a trypanosomatid parasite, is known as kinetoplast DNA. Kinetoplast DNA has a very unusual structure, consisting of several thousand minicircles and a few dozen maxicircles, all topologically interlocked into a giant network. There is one network within each cell's single mitochondrion. We previously purified a 43-kDa DNA polymerase from C. fasciculata mitochondria (Torri, A. F., and Englund, P. T. (1992) J. Biol. Chem. 267, 4786-4792). This enzyme has properties very different from those of a DNA polymerase γ, the conventional mitochondrial polymerase. In addition to its small size, it is nonprocessive, has no detectable exonuclease activity, and has very low fidelity. In all of these respects, the polymerase resembles a DNA polymerase β, a gap-filling enzyme thought to function in DNA repair in the nucleus of other eukaryotes. We speculate that this enzyme may have been specially imported into the C. fasciculata mitochondrion to repair the many gaps found in minicircles following their replication. This is the first example of a β-like polymerase from the mitochondrion of any eukaryote.
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M3 - Article
C2 - 8132542
AN - SCOPUS:0028176424
SN - 0021-9258
VL - 269
SP - 8165
EP - 8171
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 11
ER -