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PDBsum entry 2dkf
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References listed in PDB file
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Key reference
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Title
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Crystal structure of ttha0252 from thermus thermophilus hb8, A RNA degradation protein of the metallo-Beta-Lactamase superfamily.
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Authors
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H.Ishikawa,
N.Nakagawa,
S.Kuramitsu,
R.Masui.
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Ref.
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J Biochem (tokyo), 2006,
140,
535-542.
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PubMed id
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Abstract
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In bacterial RNA metabolism, mRNA degradation is an important process for gene
expression. Recently, a novel ribonuclease (RNase), belonging to the beta-CASP
family within the metallo-beta-lactamase superfamily, was identified as a
functional homologue of RNase E, a major component for mRNA degradation in
Escherichia coli. Here, we have determined the crystal structure of TTHA0252
from Thermus thermophilus HB8, which represents the first report of the tertiary
structure of a beta-CASP family protein. TTHA0252 comprises two separate
domains: a metallo-beta-lactamase domain and a "clamp" domain. The active site
of the enzyme is located in a cleft between the two domains, which includes two
zinc ions coordinated by seven conserved residues. Although this configuration
is similar to those of other beta-lactamases, TTHA0252 has one conserved His
residue characteristic of the beta-CASP family as a ligand. We also detected
nuclease activity of TTHA0252 against rRNAs of T. thermophilus. Our results
reveal structural and functional aspects of novel RNase E-like enzymes with a
beta-CASP fold.
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