A single-stranded DNA binding protein binds the origin of replication of the duplex kinetoplast DNA.
نویسندگان
چکیده
Replication of the kinetoplast DNA (kDNA) minicircle of trypanosomatids initiates at a conserved 12-nt sequence, 5'-GGGGTTGGTGTA-3', termed the universal minicircle sequence (UMS). A sequence-specific single-stranded DNA-binding protein from Crithidia fasciculata binds the heavy strand of the 12-mer UMS. Whereas this UMS-binding protein (UMSBP) does not bind a duplex UMS dodecamer, it binds the double-stranded kDNA minicircle as well as a duplex minicircle fragment containing the origin-associated UMS. Binding of the minicircle origin region by the single-stranded DNA binding protein suggested the local unwinding of the DNA double helix at this site. Modification of thymine residues at this site by KMnO4 revealed that the UMS resides within an unwound or otherwise sharply distorted DNA at the minicircle origin region. Computer analysis predicts the sequence-directed curving of the minicircle origin region. Electrophoresis of a minicircle fragment containing the origin region in polyacrylamide gels revealed a significantly lower electrophoretic mobility than expected from its length. The fragment anomalous electrophoretic mobility is displayed only in its native conformation and is dependent on temperature and gel porosity, indicating the local curving of the DNA double helix. We suggest that binding of UMSBP at the minicircle origin of replication is possible through local unwinding of the DNA double helix at the UMS site. It is hypothesized here that this local melting is initiated through the untwisting of unstacked dinucleotide sequences at the bent origin site.
منابع مشابه
Binding of the universal minicircle sequence binding protein at the kinetoplast DNA replication origin.
Kinetoplast DNA, the mitochondrial DNA of trypanosomatids, is a remarkable DNA structure that contains, in the species Crithidia fasciculata, 5000 topologically linked duplex DNA minicircles. Their replication initiates at two conserved sequences, a dodecamer, known as the universal minicircle sequence (UMS), and a hexamer, which are located at the replication origins of the minicircle L and H ...
متن کاملA single-stranded DNA-binding protein from Crithidia fasciculata recognizes the nucleotide sequence at the origin of replication of kinetoplast DNA minicircles.
A sequence-specific single-stranded DNA-binding protein from the trypanosomatid protozoan Crithidia fasciculata binds to a sequence of 12 nucleotides located at the origin of replication of kinetoplast DNA minicircles. This sequence, termed the universal minicircle sequence (UMS), is conserved in the kinetoplast DNA minicircles among species of the family Trypanosomatidae. The purified protein ...
متن کاملRedox potential regulates binding of universal minicircle sequence binding protein at the kinetoplast DNA replication origin.
Kinetoplast DNA, the mitochondrial DNA of the trypanosomatid Crithidia fasciculata, is a remarkable structure containing 5,000 topologically linked DNA minicircles. Their replication is initiated at two conserved sequences, a dodecamer, known as the universal minicircle sequence (UMS), and a hexamer, which are located at the replication origins of the minicircle L- and H-strands, respectively. ...
متن کاملUniversal minicircle sequence-binding protein, a sequence-specific DNA-binding protein that recognizes the two replication origins of the kinetoplast DNA minicircle.
Replication of the kinetoplast DNA minicircle lagging (heavy (H))-strand initiates at, or near, a unique hexameric sequence (5'-ACGCCC-3') that is conserved in the minicircles of trypanosomatid species. A protein from the trypanosomatid Crithidia fasciculata binds specifically a 14-mer sequence, consisting of the complementary strand hexamer and eight flanking nucleotides at the H-strand replic...
متن کاملجداسازی پروتئین LMG از بافت کبد موش و میانکنش آن با
ABSTRACT In eukaryote cells, DNA is complexed with a series of basic proteins making units of chromatin structure named nucleosomes. In addition, nonhistone proteins with different function are the components of chromatin. Among these proteins, a group with a low mobility on gel electrophoresis have been identified and named LMG. In this study a LMG protein with a molecular weigh of 160 ...
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ورودعنوان ژورنال:
- Proceedings of the National Academy of Sciences of the United States of America
دوره 92 23 شماره
صفحات -
تاریخ انتشار 1995