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PDBsum entry 3wc0
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Contents |
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(+ 5 more)
265 a.a.
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241 a.a.
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References listed in PDB file
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Key reference
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Title
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Structural basis of reverse nucleotide polymerization.
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Authors
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A.Nakamura,
T.Nemoto,
I.U.Heinemann,
K.Yamashita,
T.Sonoda,
K.Komoda,
I.Tanaka,
D.Söll,
M.Yao.
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Ref.
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Proc Natl Acad Sci U S A, 2013,
110,
20970-20975.
[DOI no: ]
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PubMed id
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Abstract
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Nucleotide polymerization proceeds in the forward (5'-3') direction. This tenet
of the central dogma of molecular biology is found in diverse processes
including transcription, reverse transcription, DNA replication, and even in
lagging strand synthesis where reverse polymerization (3'-5') would present a
"simpler" solution. Interestingly, reverse (3'-5') nucleotide addition
is catalyzed by the tRNA maturation enzyme tRNA(His) guanylyltransferase, a
structural homolog of canonical forward polymerases. We present a Candida
albicans tRNA(His) guanylyltransferase-tRNA(His) complex structure that reveals
the structural basis of reverse polymerization. The directionality of nucleotide
polymerization is determined by the orientation of approach of the nucleotide
substrate. The tRNA substrate enters the enzyme's active site from the opposite
direction (180° flip) compared with similar nucleotide substrates of canonical
5'-3' polymerases, and the finger domains are on opposing sides of the core palm
domain. Structural, biochemical, and phylogenetic data indicate that reverse
polymerization appeared early in evolution and resembles a mirror image of the
forward process.
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