2gjz
From Proteopedia
(New page: 200px<br /> <applet load="2gjz" size="450" color="white" frame="true" align="right" spinBox="true" caption="2gjz, resolution 2.65Å" /> '''Structure of Cataly...) |
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caption="2gjz, resolution 2.65Å" /> | caption="2gjz, resolution 2.65Å" /> | ||
'''Structure of Catalytic Elimination Antibody 13G5 from a crystal in space group P2(1)'''<br /> | '''Structure of Catalytic Elimination Antibody 13G5 from a crystal in space group P2(1)'''<br /> | ||
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==About this Structure== | ==About this Structure== | ||
| - | 2GJZ is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Mus_musculus Mus musculus] with ZN as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http:// | + | 2GJZ is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Mus_musculus Mus musculus] with <scene name='pdbligand=ZN:'>ZN</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2GJZ OCA]. |
==Reference== | ==Reference== | ||
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[[Category: immunoglobulin]] | [[Category: immunoglobulin]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri Feb 15 17:28:09 2008'' |
Revision as of 15:28, 15 February 2008
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Structure of Catalytic Elimination Antibody 13G5 from a crystal in space group P2(1)
Overview
The structure of antibody 13G5, which catalyzes the conversion of unactivated benzisoxazoles to the corresponding salicylonitriles, was determined at 2.65 Å resolution in the absence of ligand. It shows that the 2-aminobenzimidazolium derivative originally used for immunization was successful in templating an active site containing multiple functional groups. Thus, the side chains of three polar residues, AspH35, HisH95, and GluL34, project into an otherwise hydrophobic cavity. Site-directed mutagenesis and subsequent kinetic analysis identified AspH35 as the likely catalytic base that initiates proton abstraction. HisH95 appears to activate the base, whereas GluL34 may stabilize the incipient phenolate anion in the transition state at acidic pH. Introduction of alanine at position L34 unexpectedly boosts the activity of the catalyst substantially and broadens its pH optimum, perhaps because ordered water molecules are able to assume the role of proton donor over a wider range of conditions than the original glutamic acid. The aspartate base in the GluL34Ala variant provides an astonishing 109-fold rate advantage over the nonenzymatic reaction with acetate as base and exhibits an effective molarity of >106 M. These large effects illustrate the utility of bifunctional catalysis in an antibody active site for promoting reactions with unactivated substrates.
About this Structure
2GJZ is a Protein complex structure of sequences from Mus musculus with as ligand. Full crystallographic information is available from OCA.
Reference
Bifunctional catalysis of proton transfer at an antibody active site., Muller R, Debler EW, Steinmann M, Seebeck FP, Wilson IA, Hilvert D, J Am Chem Soc. 2007 Jan 24;129(3):460-1. PMID:17226987
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