4er2
From Proteopedia
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| , resolution 2.0Å | |||||||
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| Ligands: | |||||||
| Activity: | Hydrolase, with EC number 3.4.23.18, 3.4.23.28 and 3.4.23.30 3.4.21.103, 3.4.23.18, 3.4.23.28 and 3.4.23.30 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
THE ACTIVE SITE OF ASPARTIC PROTEINASES
Overview
The active site of the aspartic proteinase, endothiapepsin, has been defined by X-ray analysis and restrained least-squares refinement at 2.1 A resolution with a crystallographic agreement value of 0.16. The environments of the two catalytically important aspartyl groups are remarkably similar and the contributions of the NH2- and COOH-terminal domains to the catalytic centre are related by a local 2-fold axis. The carboxylates of the aspartyls share a hydrogen bond and have equivalent contacts to a bound water molecule or hydroxonium ion lying on the local diad. The main chains around 32 and 215 are connected by a novel interaction involving diad-related threonines. It is suggested that the two pKa values of the active site aspartyls arise from a structure not unlike that in maleic acid with a hydrogen-bonded intermediate species and a dicarboxylate characterised by electrostatic repulsions between the two negatively charged groups.
About this Structure
4ER2 is a Single protein structure of sequence from [1]. Full crystallographic information is available from OCA.
Reference
The active site of aspartic proteinases., Pearl L, Blundell T, FEBS Lett. 1984 Aug 20;174(1):96-101. PMID:6381096
Page seeded by OCA on Thu Mar 20 19:09:29 2008
