2hfy - Revision history

OCA: Protected "2hfy" [edit=sysop:move=sysop]

2012-02-01T07:12:36Z

Protected "2hfy" [edit=sysop:move=sysop]

←Older revision

Revision as of 07:12, 1 February 2012

OCA: Redirecting to 3uyn

2012-02-01T07:12:34Z

Redirecting to 3uyn

←Older revision		Revision as of 07:12, 1 February 2012
Line 1:		Line 1:
-	~~{{Seed}}~~	+	#REDIRECT [[3uyn]] This PDB entry is obsolete and replaced by 3uyn
-	[[~~Image:2hfy.png\|left\|200px~~]]	+
-		+
-	~~<!--~~	+
-	~~The line below this paragraph, containing "STRUCTURE_2hfy", creates the "Structure Box" on the page.~~	+
-	~~You may change the~~ PDB ~~parameter (which sets the PDB file loaded into the applet)~~	+
-	~~or the SCENE parameter (which sets the initial scene displayed when the page~~ is ~~loaded),~~	+
-	~~or leave the SCENE parameter empty for the default display.~~	+
-	~~-->~~	+
-	~~{{STRUCTURE_2hfy\| PDB=2hfy \| SCENE= }}~~	+
-		+
-	~~===Structural~~ and ~~kinetic analysis of proton shuttle residues in the active site of human carbonic anhydrase III===~~	+
-		+
-		+
-	~~<!--~~	+
-	~~The line below this paragraph, {{ABSTRACT_PUBMED_17427958}}, adds the Publication Abstract to the page~~	+
-	~~(as it appears on PubMed at http://www.pubmed.gov), where 17427958 is the PubMed ID number.~~	+
-	~~-->~~	+
-	~~{{ABSTRACT_PUBMED_17427958}}~~	+
-		+
-	~~==About this Structure==~~	+
-	2HFY is a 1 chain structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2HFY OCA].	+
-		+
-	~~==Reference==~~	+
-	~~<ref group="xtra">PMID:17427958</ref><references group="xtra"/>~~	+
-	~~[[Category: Carbonate dehydratase]]~~	+
-	~~[[Category: Homo sapiens]]~~	+
-	~~[[Category: Elder, I.]]~~	+
-	~~[[Category: Fisher, S Z.]]~~	+
-	~~[[Category: Laipis, P J.]]~~	+
-	~~[[Category: McKenna, R.]]~~	+
-	~~[[Category: Silverman, D N.]]~~	+
-	~~[[Category: Tu, C K.]]~~	+
-	~~[[Category: Hca iii]]~~	+
-	~~[[Category: Lyase]]~~	+
-	~~[[Category: Proton shuttle]]~~	+
-	~~[[Category: Proton transfer]]~~	+
-		+
-	~~''Page seeded~~ by ~~[http://oca.weizmann.ac.il/oca OCA ] on Tue Feb 17 12:38:26 2009''~~	+

OCA at 10:38, 17 February 2009

2009-02-17T10:38:28Z

←Older revision		Revision as of 10:38, 17 February 2009
Line 20:		Line 20:

	==About this Structure==		==About this Structure==
-	2HFY is a ~~[[Single protein]]~~ structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2HFY OCA].	+	2HFY is a 1 chain structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2HFY OCA].

	==Reference==		==Reference==
-	Structural and kinetic analysis of proton shuttle residues in the active site of human carbonic anhydrase III., Elder I, Fisher Z, Laipis PJ, Tu C, McKenna R, Silverman DN, Proteins. 2007 Jul 1;68(1):337-43. PMID:~~[http:~~//~~www.ncbi.nlm.nih.gov/pubmed/17427958 17427958]~~	+	<ref group="xtra">PMID:17427958</ref><references group="xtra"/>
	[[Category: Carbonate dehydratase]]		[[Category: Carbonate dehydratase]]
	[[Category: Homo sapiens]]		[[Category: Homo sapiens]]
-	[[Category: Single protein]]
	[[Category: Elder, I.]]		[[Category: Elder, I.]]
	[[Category: Fisher, S Z.]]		[[Category: Fisher, S Z.]]
Line 38:		Line 37:
	[[Category: Proton transfer]]		[[Category: Proton transfer]]

-	''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on ~~Mon Jul 28~~ 17:00:~~56 2008~~''	+	''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Feb 17 12:38:26 2009''

OCA at 14:00, 28 July 2008

2008-07-28T14:00:57Z

←Older revision		Revision as of 14:00, 28 July 2008
Line 1:		Line 1:
-	[[Image:2hfy.~~jpg~~\|left\|200px]]	+	{{Seed}}
		+	[[Image:2hfy.png\|left\|200px]]

	<!--		<!--
Line 9:		Line 10:
	{{STRUCTURE_2hfy\| PDB=2hfy \| SCENE= }}		{{STRUCTURE_2hfy\| PDB=2hfy \| SCENE= }}

-	~~'''~~Structural and kinetic analysis of proton shuttle residues in the active site of human carbonic anhydrase III~~'''~~	+	===Structural and kinetic analysis of proton shuttle residues in the active site of human carbonic anhydrase III===


-	~~==Overview==~~	+	<!--
-	~~We report the X~~-~~ray crystal structures and rate constants for proton transfer in site~~-~~specific mutants of human carbonic anhydrase III (HCA III) that place a histidine residue in the active-site cavity: K64H~~, ~~R67H~~, ~~and K64H-R67N HCA III. Prior evidence from~~ the ~~exchange of 18O between CO2 and water measured by mass spectrometry shows each mutant~~ to have enhanced proton transfer in catalysis compared with wild-type HCA III. However, His64 in K64H and K64H-R67N HCA III have at most a capacity for proton transfer that is only 13% that of His64 in HCA II. This reduced rate in mutants of HCA III is associated with a constrained side-chain conformation of His64, which is oriented outward, away from the ~~active-site zinc in the crystal structures. This conformation~~ appears ~~stabilized by a prominent pi stacking interaction of the imidazole ring of His64 with the indole ring of Trp5 in mutants of HCA III~~. This single orientation of His64 in K64H HCA III predominates also in a double mutant K64H-R67N HCA III, indicating that the positive charge of Arg67 does not influence the observed conformation of His64 in the crystal structure. ~~Hence~~, the ~~structures and catalytic activity of these mutants of HCA III containing His64 account only in small part for the lower activity of this isozyme compared with HCA II~~. His67 in R67H HCA III was also shown to be a proton shuttle residue, having a capacity for proton transfer that was approximately four times that of His64 in K64H HCA III. This is most likely due to its proximity and orientation inward towards the zinc-~~bound solvent. These results emphasize the significance of side chain orientation and range of available conformational states as characteristics of an efficient proton shuttle in carbonic anhydrase.~~	+	The line below this paragraph, {{ABSTRACT_PUBMED_17427958}}, adds the Publication Abstract to the page
		+	(as it appears on PubMed at http://www.pubmed.gov), where 17427958 is the PubMed ID number.
		+	-->
		+	{{ABSTRACT_PUBMED_17427958}}

	==About this Structure==		==About this Structure==
Line 33:		Line 37:
	[[Category: Proton shuttle]]		[[Category: Proton shuttle]]
	[[Category: Proton transfer]]		[[Category: Proton transfer]]
-	''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on ~~Sun May 4 06~~:14:44 2008''	+
		+	''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Jul 28 17:00:56 2008''

OCA at 03:14, 4 May 2008

2008-05-04T03:14:45Z

←Older revision		Revision as of 03:14, 4 May 2008
Line 1:		Line 1:
	[[Image:2hfy.jpg\|left\|200px]]		[[Image:2hfy.jpg\|left\|200px]]

-	~~{{Structure~~	+	<!--
-	~~\|PDB= 2hfy \|SIZE=350\|CAPTION=~~ <~~scene name='initialview01'>2hfy</scene>, resolution 2.6Å~~	+	The line below this paragraph, containing "STRUCTURE_2hfy", creates the "Structure Box" on the page.
-	~~\|SITE=~~	+	You may change the PDB parameter (which sets the PDB file loaded into the applet)
-	~~\|LIGAND= <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene>~~	+	or the SCENE parameter (which sets the initial scene displayed when the page is loaded),
-	~~\|ACTIVITY= <span class='plainlinks'>[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] </span>~~	+	or leave the SCENE parameter empty for the default display.
-	~~\|GENE= CA3~~ (~~[http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=9606 Homo sapiens]~~)	+	-->
-	~~\|DOMAIN=~~	+	{{STRUCTURE_2hfy\| PDB=2hfy \| SCENE= }}
-	~~\|RELATEDENTRY=[[2hfw\|2HFW]]~~, ~~[[2hfx\|2HFX]]~~	+
-	~~\|RESOURCES=<span class='plainlinks'>[http://oca~~.~~weizmann.ac.il/oca~~-~~docs/fgij/fg.htm?mol=2hfy FirstGlance], [http://oca.weizmann.ac.il/oca~~-~~bin/ocaids?id~~=2hfy ~~OCA], [http://www.ebi.ac.uk/pdbsum/2hfy PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId~~=~~2hfy RCSB]</span>~~	+
-	}}	+

	'''Structural and kinetic analysis of proton shuttle residues in the active site of human carbonic anhydrase III'''		'''Structural and kinetic analysis of proton shuttle residues in the active site of human carbonic anhydrase III'''
Line 32:		Line 29:
	[[Category: Silverman, D N.]]		[[Category: Silverman, D N.]]
	[[Category: Tu, C K.]]		[[Category: Tu, C K.]]
-	[[Category: ~~hca~~ iii]]	+	[[Category: Hca iii]]
-	[[Category: ~~lyase~~]]	+	[[Category: Lyase]]
-	[[Category: ~~proton~~ shuttle]]	+	[[Category: Proton shuttle]]
-	[[Category: ~~proton~~ transfer]]	+	[[Category: Proton transfer]]
-		+	''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun May 4 06:14:44 2008''
-	''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on ~~Mon Mar 31 03~~:29:53 2008''	+

OCA at 00:29, 31 March 2008

2008-03-31T00:29:57Z

←Older revision		Revision as of 00:29, 31 March 2008
Line 4:		Line 4:
	\|PDB= 2hfy \|SIZE=350\|CAPTION= <scene name='initialview01'>2hfy</scene>, resolution 2.6Å		\|PDB= 2hfy \|SIZE=350\|CAPTION= <scene name='initialview01'>2hfy</scene>, resolution 2.6Å
	\|SITE=		\|SITE=
-	\|LIGAND= <scene name='pdbligand=ZN:ZINC ION'>ZN</scene>	+	\|LIGAND= <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene>
-	\|ACTIVITY= [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]	+	\|ACTIVITY= <span class='plainlinks'>[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] </span>
	\|GENE= CA3 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=9606 Homo sapiens])		\|GENE= CA3 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=9606 Homo sapiens])
		+	\|DOMAIN=
		+	\|RELATEDENTRY=[[2hfw\|2HFW]], [[2hfx\|2HFX]]
		+	\|RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2hfy FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2hfy OCA], [http://www.ebi.ac.uk/pdbsum/2hfy PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=2hfy RCSB]</span>
	}}		}}

Line 29:		Line 32:
	[[Category: Silverman, D N.]]		[[Category: Silverman, D N.]]
	[[Category: Tu, C K.]]		[[Category: Tu, C K.]]
-	[[Category: ZN]]
	[[Category: hca iii]]		[[Category: hca iii]]
	[[Category: lyase]]		[[Category: lyase]]
Line 35:		Line 37:
	[[Category: proton transfer]]		[[Category: proton transfer]]

-	''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on ~~Thu~~ Mar ~~20 17~~:16:33 2008''	+	''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Mar 31 03:29:53 2008''

OCA at 15:16, 20 March 2008

2008-03-20T15:16:34Z

←Older revision		Revision as of 15:16, 20 March 2008
Line 1:		Line 1:
-	[[Image:2hfy.jpg\|left\|200px]]~~<br /><applet load~~="2hfy~~" size~~="350~~" color~~=~~"white" frame~~=~~"true" align="right" spinBox="true"~~	+	[[Image:2hfy.jpg\|left\|200px]]
-	~~caption="~~2hfy, resolution 2.6Å" />	+
-	'''Structural and kinetic analysis of proton shuttle residues in the active site of human carbonic anhydrase III'''~~<br />~~	+	{{Structure
		+	\|PDB= 2hfy \|SIZE=350\|CAPTION= <scene name='initialview01'>2hfy</scene>, resolution 2.6Å
		+	\|SITE=
		+	\|LIGAND= <scene name='pdbligand=ZN:ZINC ION'>ZN</scene>
		+	\|ACTIVITY= [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]
		+	\|GENE= CA3 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=9606 Homo sapiens])
		+	}}
		+
		+	'''Structural and kinetic analysis of proton shuttle residues in the active site of human carbonic anhydrase III'''
		+

	==Overview==		==Overview==
Line 7:		Line 16:

	==About this Structure==		==About this Structure==
-	2HFY 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=2HFY OCA].	+	2HFY is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2HFY OCA].

	==Reference==		==Reference==
-	Structural and kinetic analysis of proton shuttle residues in the active site of human carbonic anhydrase III., Elder I, Fisher Z, Laipis PJ, Tu C, McKenna R, Silverman DN, Proteins. 2007 Jul 1;68(1):337-43. PMID:[http://~~ispc~~.~~weizmann~~.ac.~~il/~~/~~pmbin~~/~~getpm?pmid=~~17427958 17427958]	+	Structural and kinetic analysis of proton shuttle residues in the active site of human carbonic anhydrase III., Elder I, Fisher Z, Laipis PJ, Tu C, McKenna R, Silverman DN, Proteins. 2007 Jul 1;68(1):337-43. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/17427958 17427958]
	[[Category: Carbonate dehydratase]]		[[Category: Carbonate dehydratase]]
	[[Category: Homo sapiens]]		[[Category: Homo sapiens]]
Line 26:		Line 35:
	[[Category: proton transfer]]		[[Category: proton transfer]]

-	''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu ~~Feb 21~~ 17:41:32 2008''	+	''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Mar 20 17:16:33 2008''

OCA at 15:41, 21 February 2008

2008-02-21T15:41:35Z

←Older revision		Revision as of 15:41, 21 February 2008
Line 4:		Line 4:

	==Overview==		==Overview==
-	We report the X-ray crystal structures and rate constants for proton, transfer in site-specific mutants of human carbonic anhydrase III (HCA, III) that place a histidine residue in the active-site cavity: K64H, R67H, and K64H-R67N HCA III. Prior evidence from the exchange of ~~(18)O~~ between~~, CO(2)~~ and water measured by mass spectrometry shows each mutant to have, enhanced proton transfer in catalysis compared with wild-type HCA III., However, His64 in K64H and K64H-R67N HCA III have at most a capacity for, proton transfer that is only 13% that of His64 in HCA II. This reduced, rate in mutants of HCA III is associated with a constrained side-chain, conformation of His64, which is oriented outward, away from the, active-site zinc in the crystal structures. This conformation appears, stabilized by a prominent pi stacking interaction of the imidazole ring of, His64 with the indole ring of Trp5 in mutants of HCA III. This single, orientation of His64 in K64H HCA III predominates also in a double mutant, K64H-R67N HCA III, indicating that the positive charge of Arg67 does not, influence the observed conformation of His64 in the crystal structure., Hence, the structures and catalytic activity of these mutants of HCA III, containing His64 account only in small part for the lower activity of this, isozyme compared with HCA II. His67 in R67H HCA III was also shown to be a, proton shuttle residue, having a capacity for proton transfer that was, approximately four times that of His64 in K64H HCA III. This is most, likely due to its proximity and orientation inward towards the zinc-bound, solvent. These results emphasize the significance of side chain, orientation and range of available conformational states as, characteristics of an efficient proton shuttle in carbonic anhydrase~~., Proteins 2007. (c) 2007 Wiley-Liss, Inc~~.	+	We report the X-ray crystal structures and rate constants for proton transfer in site-specific mutants of human carbonic anhydrase III (HCA III) that place a histidine residue in the active-site cavity: K64H, R67H, and K64H-R67N HCA III. Prior evidence from the exchange of 18O between CO2 and water measured by mass spectrometry shows each mutant to have enhanced proton transfer in catalysis compared with wild-type HCA III. However, His64 in K64H and K64H-R67N HCA III have at most a capacity for proton transfer that is only 13% that of His64 in HCA II. This reduced rate in mutants of HCA III is associated with a constrained side-chain conformation of His64, which is oriented outward, away from the active-site zinc in the crystal structures. This conformation appears stabilized by a prominent pi stacking interaction of the imidazole ring of His64 with the indole ring of Trp5 in mutants of HCA III. This single orientation of His64 in K64H HCA III predominates also in a double mutant K64H-R67N HCA III, indicating that the positive charge of Arg67 does not influence the observed conformation of His64 in the crystal structure. Hence, the structures and catalytic activity of these mutants of HCA III containing His64 account only in small part for the lower activity of this isozyme compared with HCA II. His67 in R67H HCA III was also shown to be a proton shuttle residue, having a capacity for proton transfer that was approximately four times that of His64 in K64H HCA III. This is most likely due to its proximity and orientation inward towards the zinc-bound solvent. These results emphasize the significance of side chain orientation and range of available conformational states as characteristics of an efficient proton shuttle in carbonic anhydrase.

	==About this Structure==		==About this Structure==
Line 10:		Line 10:

	==Reference==		==Reference==
-	Structural and kinetic analysis of proton shuttle residues in the active site of human carbonic anhydrase III., Elder I, Fisher Z, Laipis PJ, Tu C, McKenna R, Silverman DN, Proteins. 2007 ~~Apr 11~~;. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=17427958 17427958]	+	Structural and kinetic analysis of proton shuttle residues in the active site of human carbonic anhydrase III., Elder I, Fisher Z, Laipis PJ, Tu C, McKenna R, Silverman DN, Proteins. 2007 Jul 1;68(1):337-43. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=17427958 17427958]
	[[Category: Carbonate dehydratase]]		[[Category: Carbonate dehydratase]]
	[[Category: Homo sapiens]]		[[Category: Homo sapiens]]
	[[Category: Single protein]]		[[Category: Single protein]]
	[[Category: Elder, I.]]		[[Category: Elder, I.]]
-	[[Category: Fisher, S.Z.]]	+	[[Category: Fisher, S Z.]]
-	[[Category: Laipis, P.J.]]	+	[[Category: Laipis, P J.]]
	[[Category: McKenna, R.]]		[[Category: McKenna, R.]]
-	[[Category: Silverman, D.N.]]	+	[[Category: Silverman, D N.]]
-	[[Category: Tu, C.K.]]	+	[[Category: Tu, C K.]]
	[[Category: ZN]]		[[Category: ZN]]
	[[Category: hca iii]]		[[Category: hca iii]]
Line 26:		Line 26:
	[[Category: proton transfer]]		[[Category: proton transfer]]

-	''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on ~~Wed Jan 23 14~~:57:58 2008''	+	''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 17:41:32 2008''

OCA at 12:57, 23 January 2008

2008-01-23T12:57:58Z

←Older revision		Revision as of 12:57, 23 January 2008
Line 1:		Line 1:
-	[[Image:2hfy.~~gif~~\|left\|200px]]<br />	+	[[Image:2hfy.jpg\|left\|200px]]<br /><applet load="2hfy" size="350" color="white" frame="true" align="right" spinBox="true"
-	<applet load="2hfy" size="~~450~~" color="white" frame="true" align="right" spinBox="true"	+
	caption="2hfy, resolution 2.6Å" />		caption="2hfy, resolution 2.6Å" />
	'''Structural and kinetic analysis of proton shuttle residues in the active site of human carbonic anhydrase III'''<br />		'''Structural and kinetic analysis of proton shuttle residues in the active site of human carbonic anhydrase III'''<br />
Line 8:		Line 7:

	==About this Structure==		==About this Structure==
-	2HFY 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://~~ispc~~.weizmann.ac.il/oca-bin/ocashort?id=2HFY OCA].	+	2HFY 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=2HFY OCA].

	==Reference==		==Reference==
Line 27:		Line 26:
	[[Category: proton transfer]]		[[Category: proton transfer]]

-	''Page seeded by [http://~~ispc~~.weizmann.ac.il/oca OCA ] on ~~Mon Nov 12 22~~:32:~~06 2007~~''	+	''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Wed Jan 23 14:57:58 2008''

OCA: New page: 200px
'''Structural and kinet...
2007-11-12T20:25:39Z

New page: 200px<br /> <applet load="2hfy" size="450" color="white" frame="true" align="right" spinBox="true" caption="2hfy, resolution 2.6Å" /> '''Structural and kinet...

New page
[[Image:2hfy.gif|left|200px]]<br />
<applet load="2hfy" size="450" color="white" frame="true" align="right" spinBox="true"
caption="2hfy, resolution 2.6Å" />
'''Structural and kinetic analysis of proton shuttle residues in the active site of human carbonic anhydrase III'''<br />

==Overview==
We report the X-ray crystal structures and rate constants for proton, transfer in site-specific mutants of human carbonic anhydrase III (HCA, III) that place a histidine residue in the active-site cavity: K64H, R67H, and K64H-R67N HCA III. Prior evidence from the exchange of (18)O between, CO(2) and water measured by mass spectrometry shows each mutant to have, enhanced proton transfer in catalysis compared with wild-type HCA III., However, His64 in K64H and K64H-R67N HCA III have at most a capacity for, proton transfer that is only 13% that of His64 in HCA II. This reduced, rate in mutants of HCA III is associated with a constrained side-chain, conformation of His64, which is oriented outward, away from the, active-site zinc in the crystal structures. This conformation appears, stabilized by a prominent pi stacking interaction of the imidazole ring of, His64 with the indole ring of Trp5 in mutants of HCA III. This single, orientation of His64 in K64H HCA III predominates also in a double mutant, K64H-R67N HCA III, indicating that the positive charge of Arg67 does not, influence the observed conformation of His64 in the crystal structure., Hence, the structures and catalytic activity of these mutants of HCA III, containing His64 account only in small part for the lower activity of this, isozyme compared with HCA II. His67 in R67H HCA III was also shown to be a, proton shuttle residue, having a capacity for proton transfer that was, approximately four times that of His64 in K64H HCA III. This is most, likely due to its proximity and orientation inward towards the zinc-bound, solvent. These results emphasize the significance of side chain, orientation and range of available conformational states as, characteristics of an efficient proton shuttle in carbonic anhydrase., Proteins 2007. (c) 2007 Wiley-Liss, Inc.

==About this Structure==
2HFY 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://ispc.weizmann.ac.il/oca-bin/ocashort?id=2HFY OCA].

==Reference==
Structural and kinetic analysis of proton shuttle residues in the active site of human carbonic anhydrase III., Elder I, Fisher Z, Laipis PJ, Tu C, McKenna R, Silverman DN, Proteins. 2007 Apr 11;. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=17427958 17427958]
[[Category: Carbonate dehydratase]]
[[Category: Homo sapiens]]
[[Category: Single protein]]
[[Category: Elder, I.]]
[[Category: Fisher, S.Z.]]
[[Category: Laipis, P.J.]]
[[Category: McKenna, R.]]
[[Category: Silverman, D.N.]]
[[Category: Tu, C.K.]]
[[Category: ZN]]
[[Category: hca iii]]
[[Category: lyase]]
[[Category: proton shuttle]]
[[Category: proton transfer]]

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