1jfh: Difference between revisions
New page: left|200px<br /><applet load="1jfh" size="450" color="white" frame="true" align="right" spinBox="true" caption="1jfh, resolution 2.03Å" /> '''STRUCTURE OF A PANCR... |
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[[Image:1jfh.gif|left|200px]]<br /><applet load="1jfh" size=" | [[Image:1jfh.gif|left|200px]]<br /><applet load="1jfh" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="1jfh, resolution 2.03Å" /> | caption="1jfh, resolution 2.03Å" /> | ||
'''STRUCTURE OF A PANCREATIC ALPHA-AMYLASE BOUND TO A SUBSTRATE ANALOGUE AT 2.03 ANGSTROM RESOLUTION'''<br /> | '''STRUCTURE OF A PANCREATIC ALPHA-AMYLASE BOUND TO A SUBSTRATE ANALOGUE AT 2.03 ANGSTROM RESOLUTION'''<br /> | ||
==Overview== | ==Overview== | ||
The structure of pig pancreatic alpha-amylase in complex with carbohydrate | The structure of pig pancreatic alpha-amylase in complex with carbohydrate inhibitor and proteinaceous inhibitors is known but the successive events occurring at the catalytic center still remain to be elucidated. The X-ray structure analysis of a crystal of pig pancreatic alpha-amylase (PPA, EC 3.2.1.1.) soaked with an enzyme-resistant substrate analogue, methyl 4,4'-dithio-alpha-maltotrioside, showed electron density corresponding to the binding of substrate analogue molecules at the active site and at the "second binding site." The electron density observed at the active site was interpreted in terms of overlapping networks of oligosaccharides, which show binding of substrate analogue molecules at subsites prior to and subsequent to the cleavage site. A weaker patch of density observed at subsite -1 (using a nomenclature where the site of hydrolysis is taken to be between subsites -1 and +1) was modeled with water molecules. Conformational changes take place upon substrate analogue binding and the "flexible loop" that constitutes the surface edge of the active site is observed in a specific conformation. This confirms that this loop plays an important role in the recognition and binding of the ligand. The crystal structure was refined at 2.03 A resolution, to an R-factor of 16.0 (Rfree, 18.5). | ||
==About this Structure== | ==About this Structure== | ||
1JFH is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Sus_scrofa Sus scrofa] with MA2, MA3, MAN, MA1, CL, HG and CA as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Alpha-amylase Alpha-amylase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.1 3.2.1.1] Full crystallographic information is available from [http:// | 1JFH is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Sus_scrofa Sus scrofa] with <scene name='pdbligand=MA2:'>MA2</scene>, <scene name='pdbligand=MA3:'>MA3</scene>, <scene name='pdbligand=MAN:'>MAN</scene>, <scene name='pdbligand=MA1:'>MA1</scene>, <scene name='pdbligand=CL:'>CL</scene>, <scene name='pdbligand=HG:'>HG</scene> and <scene name='pdbligand=CA:'>CA</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Alpha-amylase Alpha-amylase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.1 3.2.1.1] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1JFH OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: o-glycosyl]] | [[Category: o-glycosyl]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:22:04 2008'' | ||
Revision as of 14:22, 21 February 2008
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STRUCTURE OF A PANCREATIC ALPHA-AMYLASE BOUND TO A SUBSTRATE ANALOGUE AT 2.03 ANGSTROM RESOLUTION
OverviewOverview
The structure of pig pancreatic alpha-amylase in complex with carbohydrate inhibitor and proteinaceous inhibitors is known but the successive events occurring at the catalytic center still remain to be elucidated. The X-ray structure analysis of a crystal of pig pancreatic alpha-amylase (PPA, EC 3.2.1.1.) soaked with an enzyme-resistant substrate analogue, methyl 4,4'-dithio-alpha-maltotrioside, showed electron density corresponding to the binding of substrate analogue molecules at the active site and at the "second binding site." The electron density observed at the active site was interpreted in terms of overlapping networks of oligosaccharides, which show binding of substrate analogue molecules at subsites prior to and subsequent to the cleavage site. A weaker patch of density observed at subsite -1 (using a nomenclature where the site of hydrolysis is taken to be between subsites -1 and +1) was modeled with water molecules. Conformational changes take place upon substrate analogue binding and the "flexible loop" that constitutes the surface edge of the active site is observed in a specific conformation. This confirms that this loop plays an important role in the recognition and binding of the ligand. The crystal structure was refined at 2.03 A resolution, to an R-factor of 16.0 (Rfree, 18.5).
About this StructureAbout this Structure
1JFH is a Single protein structure of sequence from Sus scrofa with , , , , , and as ligands. Active as Alpha-amylase, with EC number 3.2.1.1 Full crystallographic information is available from OCA.
ReferenceReference
Structure of a pancreatic alpha-amylase bound to a substrate analogue at 2.03 A resolution., Qian M, Spinelli S, Driguez H, Payan F, Protein Sci. 1997 Nov;6(11):2285-96. PMID:9385631
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