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PDBsum entry 3hgn
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References listed in PDB file
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Key reference
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Title
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Combined high-Resolution neutron and X-Ray analysis of inhibited elastase confirms the active-Site oxyanion hole but rules against a low-Barrier hydrogen bond.
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Authors
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T.Tamada,
T.Kinoshita,
K.Kurihara,
M.Adachi,
T.Ohhara,
K.Imai,
R.Kuroki,
T.Tada.
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Ref.
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J Am Chem Soc, 2009,
131,
11033-11040.
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PubMed id
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Abstract
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To help resolve long-standing questions regarding the catalytic activity of the
serine proteases, the structure of porcine pancreatic elastase has been analyzed
by high-resolution neutron and X-ray crystallography. To mimic the tetrahedral
transition intermediate, a peptidic inhibitor was used. A single large crystal
was used to collect room-temperature neutron data to 1.65 A resolution and X-ray
data to 1.20 A resolution. Another crystal provided a low-temperature X-ray data
set to 0.94 A resolution. The neutron data are to higher resolution than
previously reported for a serine protease and the X-ray data are comparable with
other studies. The neutron and X-ray data show that the hydrogen bond between
His57 and Asp102 (chymotrypsin numbering) is 2.60 A in length and that the
hydrogen-bonding hydrogen is 0.80-0.96 A from the histidine nitrogen. This is
not consistent with a low-barrier hydrogen which is predicted to have the
hydrogen midway between the donor and acceptor atom. The observed interaction
between His57 and Asp102 is essentially a short but conventional hydrogen bond,
sometimes described as a short ionic hydrogen bond. The neutron analysis also
shows that the oxygen of the oxopropyl group of the inhibitor is present as an
oxygen anion rather than a hydroxyl group, supporting the role of the "oxyanion
hole" in stabilizing the tetrahedral intermediate in catalysis.
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Secondary reference #1
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Title
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Crystallization of porcine pancreatic elastase and a preliminary neutron diffraction experiment
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Authors
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T.Kinoshita,
T.Tamada,
K.Imai,
K.Kurihara,
T.Ohhara,
T.Tada,
R.Kuroki.
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Ref.
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acta crystallogr ,sect f, 2007,
63,
315.
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PubMed id
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