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Endonuclease (R) subunits of type‐I and type‐III restriction‐modification enzymes contain a helicase‐like domain
Author(s) -
Gorbalenya Alexander E.,
Koonin Eugene V.
Publication year - 1991
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(91)81301-n
Subject(s) - helicase , restriction enzyme , biochemistry , dna , biology , enzyme , endonuclease , rna helicase a , nucleic acid , cleavage (geology) , microbiology and biotechnology , protein subunit , genetics , rna , gene , paleontology , fracture (geology)
A statistically significant amino acid sequence similarity is demonstrated between the endonuclease (R) subunit of Eco K restriction‐modification (R‐M) enzyme, and RNA and DNA helicases of the so‐called ‘DEAD’ family. It is further shown that all three known sequences of R subunits of type‐I and type‐III R‐M enzymes contain the conserved amino acid sequence motifs typical of the previously described helicase superfamily II [(1989) Nucleic Acids Res. 17, 4713–4730]. A hypothesis is proposed that these enzymes may exert helicase activity possibly required for local unwinding of DNA in the cleavage sites.