Publication Date:
1996-07-05
Description:
When the Mg2+ ion in the catalytic center of Escherichia coli RNA polymerase (RNAP) is replaced with Fe2+, hydroxyl radicals are generated. In the promoter complex, such radicals cleave template DNA near the transcription start site, whereas the beta' subunit is cleaved at a conserved motif NADFDGD (Asn-Ala-Asp-Phe-Asp-Gly-Asp). Substitution of the three aspartate residues with alanine creates a dominant lethal mutation. The mutant RNAP is catalytically inactive but can bind promoters and form an open complex. The mutant fails to support Fe2+-induced cleavage of DNA or protein. Thus, the NAD-FDGD motif is involved in chelation of the active center Mg2+.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Zaychikov, E -- Martin, E -- Denissova, L -- Kozlov, M -- Markovtsov, V -- Kashlev, M -- Heumann, H -- Nikiforov, V -- Goldfarb, A -- Mustaev, A -- New York, N.Y. -- Science. 1996 Jul 5;273(5271):107-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Limnological Institute, Russian Academy of Sciences, Irkutsk, Russia.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8658176" target="_blank"〉PubMed〈/a〉
Keywords:
Amino Acid Sequence
;
Aspartic Acid/metabolism
;
Binding Sites
;
DNA/metabolism
;
DNA-Directed RNA Polymerases/*chemistry/genetics/*metabolism
;
Dithiothreitol/pharmacology
;
Electrophoresis, Polyacrylamide Gel
;
Escherichia coli/*enzymology
;
Ferrous Compounds/metabolism
;
Hydroxyl Radical
;
Magnesium/metabolism
;
Molecular Sequence Data
;
Mutagenesis
;
Promoter Regions, Genetic
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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