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Title
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Three-dimensional structure of ribonuclease H from E. coli.
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Authors
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K.Katayanagi,
M.Miyagawa,
M.Matsushima,
M.Ishikawa,
S.Kanaya,
M.Ikehara,
T.Matsuzaki,
K.Morikawa.
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Ref.
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Nature, 1990,
347,
306-309.
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PubMed id
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Abstract
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The three-dimensional structure of RNase H from Escherichia coli was determined
at 1.8 A resolution by X-ray crystallography. The enzyme was found to belong to
the alpha + beta class of structures, consisting of two distinct domains. The
structure implies a possible region interacting with a DNA-RNA hybrid. The
Mg2(+)-binding site essential for activity is located near a cluster of four
acidic amino acids--one glutamic and three aspartic acid residues. These
residues are completely conserved in the homology alignment of sequences of
RNase H and reverse transcriptases from retroviruses and retrovirus-like
entities. The structural motif of beta strands around the Mg2(+)-binding site
has similarities to that in DNase I.
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