1bx3: Difference between revisions
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[[Image: | ==EFFECTS OF COMMONLY USED CRYOPROTECTANTS ON GLYCOGEN PHOSPHORYLASE ACTIVITY AND STRUCTURE== | ||
<StructureSection load='1bx3' size='340' side='right' caption='[[1bx3]], [[Resolution|resolution]] 2.30Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[1bx3]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Oryctolagus_cuniculus Oryctolagus cuniculus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1BX3 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1BX3 FirstGlance]. <br> | |||
</td></tr><tr><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=PLP:PYRIDOXAL-5-PHOSPHATE'>PLP</scene><br> | |||
<tr><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Phosphorylase Phosphorylase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.4.1.1 2.4.1.1] </span></td></tr> | |||
<tr><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1bx3 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1bx3 OCA], [http://www.rcsb.org/pdb/explore.do?structureId=1bx3 RCSB], [http://www.ebi.ac.uk/pdbsum/1bx3 PDBsum]</span></td></tr> | |||
<table> | |||
== Evolutionary Conservation == | |||
[[Image:Consurf_key_small.gif|200px|right]] | |||
Check<jmol> | |||
<jmolCheckbox> | |||
<scriptWhenChecked>select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/bx/1bx3_consurf.spt"</scriptWhenChecked> | |||
<scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked> | |||
<text>to colour the structure by Evolutionary Conservation</text> | |||
</jmolCheckbox> | |||
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/chain_selection.php?pdb_ID=2ata ConSurf]. | |||
<div style="clear:both"></div> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
The effects of a number of cryoprotectants on the kinetic and structural properties of glycogen phosphorylase b have been investigated. Kinetic studies showed that glycerol, one of the most commonly used cryoprotectants in X-ray crystallographic studies, is a competitive inhibitor with respect to substrate glucose-1-P with an apparent Ki value of 3.8% (v/v). Cryogenic experiments, with the enzyme, have shown that glycerol binds at the catalytic site and competes with glucose analogues that bind at the catalytic site, thus preventing the formation of complexes. This necessitated a change in the conditions for cryoprotection in crystallographic binding experiments with glycogen phosphorylase. It was found that 2-methyl-2,4-pentanediol (MPD), polyethylene glycols (PEGs) of various molecular weights, and dimethyl sulfoxide (DMSO) activated glycogen phosphorylase b to different extents, by stabilizing its most active conformation, while sucrose acted as a noncompetitive inhibitor and ethylene glycol as an uncompetitive inhibitor with respect to glucose-1-P. A parallel experimental investigation by X-ray crystallography showed that, at 100 K, both MPD and DMSO do not bind at the catalytic site, do not induce any significant conformational change on the enzyme molecule, and hence, are more suitable cryoprotectants than glycerol for binding studies with glycogen phosphorylase. | |||
Effects of commonly used cryoprotectants on glycogen phosphorylase activity and structure.,Tsitsanou KE, Oikonomakos NG, Zographos SE, Skamnaki VT, Gregoriou M, Watson KA, Johnson LN, Fleet GW Protein Sci. 1999 Apr;8(4):741-9. PMID:10211820<ref>PMID:10211820</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
==See Also== | ==See Also== | ||
*[[Glycogen Phosphorylase|Glycogen Phosphorylase]] | *[[Glycogen Phosphorylase|Glycogen Phosphorylase]] | ||
== References == | |||
== | <references/> | ||
< | __TOC__ | ||
</StructureSection> | |||
[[Category: Oryctolagus cuniculus]] | [[Category: Oryctolagus cuniculus]] | ||
[[Category: Phosphorylase]] | [[Category: Phosphorylase]] | ||
Revision as of 12:41, 13 August 2014
EFFECTS OF COMMONLY USED CRYOPROTECTANTS ON GLYCOGEN PHOSPHORYLASE ACTIVITY AND STRUCTUREEFFECTS OF COMMONLY USED CRYOPROTECTANTS ON GLYCOGEN PHOSPHORYLASE ACTIVITY AND STRUCTURE
Structural highlights
Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe effects of a number of cryoprotectants on the kinetic and structural properties of glycogen phosphorylase b have been investigated. Kinetic studies showed that glycerol, one of the most commonly used cryoprotectants in X-ray crystallographic studies, is a competitive inhibitor with respect to substrate glucose-1-P with an apparent Ki value of 3.8% (v/v). Cryogenic experiments, with the enzyme, have shown that glycerol binds at the catalytic site and competes with glucose analogues that bind at the catalytic site, thus preventing the formation of complexes. This necessitated a change in the conditions for cryoprotection in crystallographic binding experiments with glycogen phosphorylase. It was found that 2-methyl-2,4-pentanediol (MPD), polyethylene glycols (PEGs) of various molecular weights, and dimethyl sulfoxide (DMSO) activated glycogen phosphorylase b to different extents, by stabilizing its most active conformation, while sucrose acted as a noncompetitive inhibitor and ethylene glycol as an uncompetitive inhibitor with respect to glucose-1-P. A parallel experimental investigation by X-ray crystallography showed that, at 100 K, both MPD and DMSO do not bind at the catalytic site, do not induce any significant conformational change on the enzyme molecule, and hence, are more suitable cryoprotectants than glycerol for binding studies with glycogen phosphorylase. Effects of commonly used cryoprotectants on glycogen phosphorylase activity and structure.,Tsitsanou KE, Oikonomakos NG, Zographos SE, Skamnaki VT, Gregoriou M, Watson KA, Johnson LN, Fleet GW Protein Sci. 1999 Apr;8(4):741-9. PMID:10211820[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences |
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