1g0f
From Proteopedia
(New page: 200px<br /> <applet load="1g0f" size="450" color="white" frame="true" align="right" spinBox="true" caption="1g0f, resolution 1.60Å" /> '''SITE-SPECIFIC MUTAN...) |
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caption="1g0f, resolution 1.60Å" /> | caption="1g0f, resolution 1.60Å" /> | ||
'''SITE-SPECIFIC MUTANT (HIS64 REPLACED WITH ALA) OF HUMAN CARBONIC ANHYDRASE II'''<br /> | '''SITE-SPECIFIC MUTANT (HIS64 REPLACED WITH ALA) OF HUMAN CARBONIC ANHYDRASE II'''<br /> | ||
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==About this Structure== | ==About this Structure== | ||
| - | 1G0F 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 and HG as [http://en.wikipedia.org/wiki/ligands ligands]. 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:// | + | 1G0F 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> and <scene name='pdbligand=HG:'>HG</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. 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=1G0F OCA]. |
==Reference== | ==Reference== | ||
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[[Category: zinc metalloenzyme]] | [[Category: zinc metalloenzyme]] | ||
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Revision as of 13:50, 15 February 2008
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SITE-SPECIFIC MUTANT (HIS64 REPLACED WITH ALA) OF HUMAN CARBONIC ANHYDRASE II
Contents |
Overview
Histidine 64 in human carbonic anhydrase II (HCA II) functions in the, catalytic pathway of CO(2) hydration as a shuttle to transfer protons, between the zinc-bound water and bulk water. Catalysis of the exchange of, (18)O between CO(2) and water, measured by mass spectrometry, is dependent, on this proton transfer and was decreased more than 10-fold for H64A HCA, II compared with wild-type HCA II. The loss of catalytic activity of H64A, HCA II could be rescued by 4-methylimidazole (4-MI), an exogenous proton, donor, in a saturable process with a maximum activity of 40% of wild-type, HCA II. The crystal structure of the rescued complex at 1.6 A resolution, shows 4-MI bound in the active-site cavity of H64A HCA II, through pi, stacking interactions with Trp 5 and H-bonding interactions with water, molecules. In this location, 4-MI is about 12 A from the zinc and, approximates the observed "out" position of His 64 in the structure of the, wild-type enzyme. 4-MI appears to compensate for the absence of His 64 and, rescues the catalytic activity of the H64A HCA II mutant. This result, strongly suggests that the out conformation of His 64 is effective in the, transfer of protons between the zinc-bound solvent molecule and solution.
Disease
Known disease associated with this structure: Osteopetrosis, autosomal recessive 3, with renal tubular acidosis OMIM:[611492]
About this Structure
1G0F is a Single protein structure of sequence from Homo sapiens with and as ligands. Active as Carbonate dehydratase, with EC number 4.2.1.1 Full crystallographic information is available from OCA.
Reference
Structural and kinetic analysis of the chemical rescue of the proton transfer function of carbonic anhydrase II., Duda D, Tu C, Qian M, Laipis P, Agbandje-McKenna M, Silverman DN, McKenna R, Biochemistry. 2001 Feb 13;40(6):1741-8. PMID:11327835
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