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1cct
From Proteopedia
(New page: 200px<br /> <applet load="1cct" size="450" color="white" frame="true" align="right" spinBox="true" caption="1cct, resolution 2.2Å" /> '''STRUCTURE-ASSISTED R...) |
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caption="1cct, resolution 2.2Å" /> | caption="1cct, resolution 2.2Å" /> | ||
'''STRUCTURE-ASSISTED REDESIGN OF A PROTEIN-ZINC BINDING SITE WITH FEMTOMOLAR AFFINITY'''<br /> | '''STRUCTURE-ASSISTED REDESIGN OF A PROTEIN-ZINC BINDING SITE WITH FEMTOMOLAR AFFINITY'''<br /> | ||
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==About this Structure== | ==About this Structure== | ||
| - | 1CCT is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with ZN as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Carbonate_dehydratase Carbonate dehydratase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=4.2.1.1 4.2.1.1] Full crystallographic information is available from [http:// | + | 1CCT is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with <scene name='pdbligand=ZN:'>ZN</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Carbonate_dehydratase Carbonate dehydratase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=4.2.1.1 4.2.1.1] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1CCT OCA]. |
==Reference== | ==Reference== | ||
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[[Category: lyase (oxo-acid)]] | [[Category: lyase (oxo-acid)]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri Feb 15 15:35:11 2008'' |
Revision as of 13:35, 15 February 2008
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STRUCTURE-ASSISTED REDESIGN OF A PROTEIN-ZINC BINDING SITE WITH FEMTOMOLAR AFFINITY
Contents |
Overview
We have inserted a fourth protein ligand into the zinc coordination, polyhedron of carbonic anhydrase II (CAII) that increases metal affinity, 200-fold (Kd = 20 fM). The three-dimensional structures of, threonine-199-->aspartate (T199D) and threonine-199-->glutamate (T199E), CAIIs, determined by x-ray crystallographic methods to resolutions of 2.35, Angstrum and 2.2 Angstrum, respectively, reveal a tetrahedral, metal-binding site consisting of H94, H96, H119, and the engineered, carboxylate side chain, which displaces zinc-bound hydroxide. Although the, stereochemistry of neither engineered carboxylate-zinc interaction is, comparable to that found in naturally occurring protein zinc-binding, sites, protein-zinc affinity is enhanced in T199E CAII demonstrating that, ligand-metal separation is a significant determinant of carboxylate-zinc, affinity. In contrast, the three-dimensional structure of, threonine-199-->histidine (T199H) CAII, determined to 2.25-Angstrum, resolution, indicates that the engineered imidazole side chain rotates, away from the metal and does not coordinate to zinc; this results in a, weaker zinc-binding site. All three of these substitutions nearly, obliterate CO2 hydrase activity, consistent with the role of zinc-bound, hydroxide as catalytic nucleophile. The engineering of an additional, protein ligand represents a general approach for increasing protein-metal, affinity if the side chain can adopt a reasonable conformation and achieve, inner-sphere zinc coordination. Moreover, this structure-assisted design, approach may be effective in the development of high-sensitivity metal ion, biosensors.
Disease
Known disease associated with this structure: Osteopetrosis, autosomal recessive 3, with renal tubular acidosis OMIM:[611492]
About this Structure
1CCT is a Single protein structure of sequence from Homo sapiens with as ligand. Active as Carbonate dehydratase, with EC number 4.2.1.1 Full crystallographic information is available from OCA.
Reference
Structure-assisted redesign of a protein-zinc-binding site with femtomolar affinity., Ippolito JA, Baird TT Jr, McGee SA, Christianson DW, Fierke CA, Proc Natl Acad Sci U S A. 1995 May 23;92(11):5017-21. PMID:7761440
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