1wcq: Difference between revisions
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[[Image:1wcq.gif|left|200px]]<br /><applet load="1wcq" size=" | [[Image:1wcq.gif|left|200px]]<br /><applet load="1wcq" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="1wcq, resolution 2.10Å" /> | caption="1wcq, resolution 2.10Å" /> | ||
'''MUTAGENESIS OF THE NUCLEOPHILIC TYROSINE IN A BACTERIAL SIALIDASE TO PHENYLALANINE.'''<br /> | '''MUTAGENESIS OF THE NUCLEOPHILIC TYROSINE IN A BACTERIAL SIALIDASE TO PHENYLALANINE.'''<br /> | ||
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==About this Structure== | ==About this Structure== | ||
1WCQ is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Micromonospora_viridifaciens Micromonospora viridifaciens] with NA, DAN and GOL as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Exo-alpha-sialidase Exo-alpha-sialidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.18 3.2.1.18] Known structural/functional Site: <scene name='pdbsite=AC1:Dan Binding Site For Chain C'>AC1</scene>. Full crystallographic information is available from [http:// | 1WCQ is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Micromonospora_viridifaciens Micromonospora viridifaciens] with <scene name='pdbligand=NA:'>NA</scene>, <scene name='pdbligand=DAN:'>DAN</scene> and <scene name='pdbligand=GOL:'>GOL</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Exo-alpha-sialidase Exo-alpha-sialidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.18 3.2.1.18] Known structural/functional Site: <scene name='pdbsite=AC1:Dan+Binding+Site+For+Chain+C'>AC1</scene>. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1WCQ OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: sialidase]] | [[Category: sialidase]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Feb 3 10:21:49 2008'' | ||
Revision as of 11:21, 3 February 2008
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MUTAGENESIS OF THE NUCLEOPHILIC TYROSINE IN A BACTERIAL SIALIDASE TO PHENYLALANINE.
OverviewOverview
Mutants of the Micromonospora viridifaciens sialidase, Y370E and Y370F, are catalytically active retaining enzymes that operate by different, mechanisms. Previous substitutions with smaller amino acids, including, Y370D, yielded inverting sialidases. At least one water molecule can fit, into the active-site cavity of this mutant and act as a nucleophile from, the face opposite the leaving group (Biochemistry 2003, 42, 12 682). Thus, addition of a CH(2) unit (Asp versus Glu) changes the mechanism from, inversion back to retention of configuration. Based on Bronsted beta(lg), values, it is proposed that the Y370E mutant reacts by a, double-displacement mechanism (beta(lg) on k(cat)/K(m) -0.36+/-0.04) with, Glu370 acting as the nucleophile. However, the Y370F mutant (beta(lg) on, k(cat)/K(m) -0.79+/-0.12) reacts via a dissociative transition state. The, crystal structure of the Y370F mutant complexed with, 2-deoxy-2,3-dehydro-N-acetylneuraminic acid shows no significant, active-site perturbation relative to the wild-type enzyme.
About this StructureAbout this Structure
1WCQ is a Single protein structure of sequence from Micromonospora viridifaciens with , and as ligands. Active as Exo-alpha-sialidase, with EC number 3.2.1.18 Known structural/functional Site: . Full crystallographic information is available from OCA.
ReferenceReference
Two nucleophilic mutants of the Micromonospora viridifaciens sialidase operate with retention of configuration by two different mechanisms., Watson JN, Newstead S, Narine AA, Taylor G, Bennet AJ, Chembiochem. 2005 Nov;6(11):1999-2004. PMID:16206228
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