Abstract
QueF (MW = 19.4 kDa) is a recently characterized nitrile oxidoreductase which catalyzes the NADPH-dependent reduction of 7-cyano-7-deazaguanine (preQ0) to 7-aminomethyl-7-deazaguanine, a late step in the biosynthesis of the modified tRNA nucleoside queuosine. Initial crystals of homododecameric Bacillus subtilis QueF diffracted poorly to 8.0 A. A three-dimensional model based on homology with the tunnel-fold enzyme GTP cyclohydrolase I suggested catalysis at intersubunit interfaces and a potential role for substrate binding in quaternary structure stabilization. Guided by this insight, a second crystal form was grown that was strictly dependent on the presence of preQ0. This crystal form diffracted to 2.25 A resolution.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
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Bacillus subtilis / enzymology*
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Bacillus subtilis / metabolism
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Catalysis
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Computational Biology
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Crystallization
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Crystallography, X-Ray / methods*
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GTP Cyclohydrolase / chemistry
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Guanine / analogs & derivatives
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Guanine / chemistry
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Models, Chemical
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Models, Molecular
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NADP / chemistry
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Nucleoside Q / chemistry*
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Oxidoreductases / chemistry*
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Protein Conformation
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Protein Isoforms
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Protein Structure, Tertiary
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Pyrimidinones / chemistry
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Pyrroles / chemistry
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RNA Processing, Post-Transcriptional
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RNA, Transfer / chemistry
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X-Ray Diffraction
Substances
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7-(aminomethyl)-7-deazaguanine
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Protein Isoforms
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Pyrimidinones
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Pyrroles
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NADP
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Nucleoside Q
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Guanine
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RNA, Transfer
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Oxidoreductases
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GTP Cyclohydrolase
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7-deazaguanine