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1‐Methyl‐4‐phenylpyridinium ion, a toxin that can cause parkinsonism, alters branched structures of DNA
Author(s) -
Iwaasa Mitsutoshi,
Umeda Shuyo,
Ohsato Takashi,
Takamatsu Chihiro,
Fukuoh Atushi,
Iwasaki Hiroshi,
Shinagawa Hideo,
Hamasaki Naotaka,
Kang Dongchon
Publication year - 2002
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.2002.00996.x
Subject(s) - helicase , cruciform , dna , mitochondrial dna , dna replication , biology , holliday junction , biophysics , stereochemistry , mitochondrion , dna supercoil , microbiology and biotechnology , chemistry , genetics , dna repair , gene , materials science , rna , composite material
During replication, human mitochondrial DNA (mtDNA) takes on a triple‐stranded structure known as a D‐loop, which is implicated in replication and transcription. 1‐Methyl‐4‐phenylpyridinium ion (MPP + ), a toxin inducing parkinsonism, inhibits mtDNA replication, possibly by resolving the D‐loops. For initiation of mtDNA replication, mitochondria are thought to have another triple‐stranded structure, an R‐loop. The R‐loop, which is resolved by a bacterial junction‐specific helicase, RecG, is also resolved by MPP + . Because mitochondrial D‐loops are likewise resolved by RecG, the D‐ and R‐loops may share a similar branched structure. MPP + resolves cruciform DNA in supercoiled DNA. MPP + converts a stacked conformation to an extended conformation in a synthetic Holliday junction. This conversion is reversed by 1 m m Mg 2+ , as is the resolution of the D‐loops or cruciform DNA. These observations suggest that the junction structure of mitochondrial D‐ and R‐loops is affected by MPP + .