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Iterative Optimization of DNA Duplexes for Crystallization of SeqA-DNA Complexes
Published on: November 1, 2012
Crystal structure of metagenome-derived LC9-RNase H1 with atypical DEDN active site motif
Tri-Nhan Nguyen1, Dong-Ju You, Eiko Kanaya
1Department of Material and Life Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
Abstract:
The crystal structure of metagenome-derived LC9-RNase H1 was determined. The structure-based mutational analyses indicated that the active site motif of LC9-RNase H1 is altered from DEDD to DEDN. In this motif, the location of the second glutamate residue is moved from αA-helix to β1-strand immediately next to the first aspartate residue, as in the active site of RNase H2. However, the structure and enzymatic properties of LC9-RNase H1 highly resemble those of RNase H1, instead of RNase H2. We propose that LC9-RNase H1 represents bacterial RNases H1 with an atypical DEDN active site motif, which are evolutionarily distinct from those with a typical DEDD active site motif.
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