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Crystal structure of Nae I—an evolutionary bridge between DNA endonuclease and topoisomerase
Author(s) -
Huai Qing,
Colandene James D.,
Chen Yongquan,
Luo Feng,
Zhao Yingdong,
Topal Michael D.,
Ke Hengming
Publication year - 2000
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/19.12.3110
Subject(s) - biology , endonuclease , dna , topoisomerase , dna supercoil , dna clamp , biochemistry , exonuclease , genetics , microbiology and biotechnology , dna polymerase , dna replication , gene , rna , reverse transcriptase
Nae I is transformed from DNA endonuclease to DNA topoisomerase and recombinase by a single amino acid substitution. The crystal structure of Nae I was solved at 2.3 Å resolution and shows that Nae I is a dimeric molecule with two domains per monomer. Each domain contains one potential DNA recognition motif corresponding to either endonuclease or topoisomerase activity. The N‐terminal domain core folds like the other type II restriction endonucleases as well as λ‐exonuclease and the DNA repair enzymes MutH and Vsr, implying a common evolutionary origin and catalytic mechanism. The C‐terminal domain contains a catabolite activator protein (CAP) motif present in many DNA‐binding proteins, including the type IA and type II topoisomerases. Thus, the Nae I structure implies that DNA processing enzymes evolved from a few common ancestors. Nae I may be an evolutionary bridge between endonuclease and DNA processing enzymes.