FROM RNA TO DNA, WHY SO MANY RIBONUCLEOTIDE REDUCTASES

Authors
Citation
P. Reichard, FROM RNA TO DNA, WHY SO MANY RIBONUCLEOTIDE REDUCTASES, Science, 260(5115), 1993, pp. 1773-1777
Citations number
50
Categorie Soggetti
Multidisciplinary Sciences
Journal title
ISSN journal
00368075
Volume
260
Issue
5115
Year of publication
1993
Pages
1773 - 1777
Database
ISI
SICI code
0036-8075(1993)260:5115<1773:FRTDWS>2.0.ZU;2-R
Abstract
It is generally accepted that DNA appeared after RNA during the chemic al evolution of life. To synthesize DNA, deoxyribonucleotides are requ ired as building blocks. At present, these are formed from the corresp onding ribonucleotides through the enzymatic action of ribonucleotide reductases. Three classes of enzymes are present in various organisms. There is little sequence similarity among the three classes of reduct ases. However, enzymic mechanisms and the allosteric behavior of the e nzymes from various organisms are strongly conserved, suggesting that the enzymes might have evolved from a common ancestor, with the class III anaerobic Escherichia coli reductase as its closest relative.