| RRC ID |
30166
|
| 著者 |
Nakahigashi K, Kubo N, Narita S, Shimaoka T, Goto S, Oshima T, Mori H, Maeda M, Wada C, Inokuchi H.
|
| タイトル |
HemK, a class of protein methyl transferase with similarity to DNA methyl transferases, methylates polypeptide chain release factors, and hemK knockout induces defects in translational termination.
|
| ジャーナル |
Proc Natl Acad Sci U S A
|
| Abstract |
HemK, a universally conserved protein of unknown function, has high amino acid similarity with DNA-(adenine-N6) methyl transferases (MTases). A certain mutation in hemK gene rescues the photosensitive phenotype of a ferrochelatase-deficient (hemH) mutant in Escherichia coli. A hemK knockout strain of E. coli not only suffered severe growth defects, but also showed a global shift in gene expression to anaerobic respiration, as determined by microarray analysis, and this shift may lead to the abrogation of photosensitivity by reducing the oxidative stress. Suppressor mutations that abrogated the growth defects of the hemK knockout strain were isolated and shown to be caused by a threonine to alanine change at codon 246 of polypeptide chain release factor (RF) 2, indicating that hemK plays a role in translational termination. Consistent with such a role, the hemK knockout strain showed an enhanced rate of read-through of nonsense codons and induction of transfer-mRNA-mediated tagging of proteins within the cell. By analysis of the methylation of RF1 and RF2 in vivo and in vitro, we showed that HemK methylates RF1 and RF2 in vitro within the tryptic fragment containing the conserved GGQ motif, and that hemK is required for the methylation within the same fragment of, at least, RF1 in vivo. This is an example of a protein MTase containing the DNA MTase motif and also a protein-(glutamine-N5) MTase.
|
| 巻・号 |
99(3)
|
| ページ |
1473-8
|
| 公開日 |
2002-2-5
|
| DOI |
10.1073/pnas.032488499
|
| PII |
032488499
|
| PMID |
11805295
|
| PMC |
PMC122215
|
| MeSH |
Amino Acid Sequence
Anaerobiosis
Binding Sites
Cloning, Molecular
Culture Media
Escherichia coli / enzymology
Escherichia coli / genetics*
Escherichia coli / growth & development
Escherichia coli Proteins / genetics
Escherichia coli Proteins / metabolism*
Gene Deletion
Gene Expression Regulation, Bacterial
Kinetics
Methylation
Mutation, Missense
Oxidative Stress
Oxygen Consumption
Peptide Chain Termination, Translational / genetics*
Protein Methyltransferases / genetics*
Protein Methyltransferases / metabolism*
Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
Suppression, Genetic
beta-Galactosidase / genetics
|
| IF |
9.412
|
| 引用数 |
81
|
|
WOS 分野
|
BIOCHEMISTRY & MOLECULAR BIOLOGY
|
| リソース情報 |
| 原核生物(大腸菌) |
IH98
IH92 |
