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PDBsum entry 1g5c
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Contents |
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* Residue conservation analysis
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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 the "cab"-Type beta class carbonic anhydrase from the archaeon methanobacterium thermoautotrophicum.
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Authors
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P.Strop,
K.S.Smith,
T.M.Iverson,
J.G.Ferry,
D.C.Rees.
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Ref.
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J Biol Chem, 2001,
276,
10299-10305.
[DOI no: ]
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PubMed id
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Abstract
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The structure of the "cab"-type beta class carbonic anhydrase from the
archaeon Methanobacterium thermoautotrophicum (Cab) has been determined to 2.1-A
resolution using the multiwavelength anomalous diffraction phasing technique.
Cab exists as a dimer with a subunit fold similar to that observed in
"plant"-type beta class carbonic anhydrases. The active site zinc is
coordinated by protein ligands Cys(32), His(87), and Cys(90), with the
tetrahedral coordination completed by a water molecule. The major difference
between plant- and cab-type beta class carbonic anhydrases is in the
organization of the hydrophobic pocket. The structure reveals a Hepes buffer
molecule bound 8 A away from the active site zinc, which suggests a possible
proton transfer pathway from the active site to the solvent.
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Figure 1.
Fig. 1. Alignment of  -CA
sequences. Cab, M. thermoautotrophicum; PPnterm, P. purpureum
N-terminal domain; PPcterm, P. purpureum C-terminal domain;
P.S., P. sativum; ECcynT, E. coli. Zinc ligands are colored
yellow, the conserved Asp/Arg pair is red, and residues
differentiating cab-type and plant-type are blue.
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Figure 6.
Fig. 6. Stereo diagram showing the superposition of the
active site of Cab , P. sativum, and P. purpureum -CAs
including zinc, zinc-coordinating residues, and the conserved
residues differentiating between cab- and plant-type -CA. A, Cab
is shown in yellow; P. sativum -CA is shown
in green. The coordinating water molecule in Cab is shown in
red. B, Cab is shown in yellow; P. purpureum -CA is shown
in blue. The coordinating water molecule in Cab is shown in red.
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The above figures are
reprinted
by permission from the ASBMB:
J Biol Chem
(2001,
276,
10299-10305)
copyright 2001.
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