2ber
From Proteopedia
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| - | [[Image:2ber.gif|left|200px]]<br /><applet load="2ber" size=" | + | [[Image:2ber.gif|left|200px]]<br /><applet load="2ber" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="2ber, resolution 1.80Å" /> | caption="2ber, resolution 1.80Å" /> | ||
'''Y370G ACTIVE SITE MUTANT OF THE SIALIDASE FROM MICROMONOSPORA VIRIDIFACIENS IN COMPLEX WITH BETA-NEU5AC (SIALIC ACID).'''<br /> | '''Y370G ACTIVE SITE MUTANT OF THE SIALIDASE FROM MICROMONOSPORA VIRIDIFACIENS IN COMPLEX WITH BETA-NEU5AC (SIALIC ACID).'''<br /> | ||
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==About this Structure== | ==About this Structure== | ||
| - | 2BER 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 SLB and NA 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:Na Binding Site For Chain A'>AC1</scene>. Full crystallographic information is available from [http:// | + | 2BER 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=SLB:'>SLB</scene> and <scene name='pdbligand=NA:'>NA</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:Na+Binding+Site+For+Chain+A'>AC1</scene>. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2BER 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 10:23:10 2008'' |
Revision as of 08:23, 3 February 2008
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Y370G ACTIVE SITE MUTANT OF THE SIALIDASE FROM MICROMONOSPORA VIRIDIFACIENS IN COMPLEX WITH BETA-NEU5AC (SIALIC ACID).
Overview
Mutagenesis of the conserved tyrosine (Y370) of the Micromonospora, viridifaciens sialidase to small amino acids changes the mechanism of, catalysis from retention of anomeric configuration to inversion [Watson, J. N., et al. (2003) Biochemistry 42, 12682-12690]. For the Y370G mutant, enzyme-catalyzed hydrolysis of a series of aryl sialosides and, 3'-sialyllactose, the derived Bronsted parameters (beta(lg)) on k(cat) and, k(cat)/K(m) are -0.63 +/- 0.05 and -0.80 +/- 0.08, respectively. Thus, for, the Y370G enzyme, glycosidic C-O bond cleavage is rate-determining., Analysis of the activity of the Y370G mutant and wild-type enzymes against, a substrate [3,4-dihydro-2H-pyrano[3,2-c]pyridinium, alpha-d-N-acetylneuraminide (DHP-alphaNeu5Ac)] whose hydrolysis cannot be, accelerated by acid catalysis is consistent with these reactions, proceeding via S(N)1 and S(N)2 mechanisms, respectively. The overall, structure of the Y370G mutant sialidase active site is very similar to the, previously reported wild-type structure [Gaskell, A., et al. (1995), Structure 3, 1197-1205], although removal of the tyrosine residue creates, two significant changes to the active site. First, the anomeric oxygen, atom of the hydrolysis product (beta-N-acetylneuraminic acid) and four, water molecules bind in the large cavity created by the Y370G mutation., Second, the side chain of Asn310 moves to make a strong hydrogen bond to, one of the bound water molecules.
About this Structure
2BER 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.
Reference
Structure and mechanism of action of an inverting mutant sialidase., Newstead S, Watson JN, Knoll TL, Bennet AJ, Taylor G, Biochemistry. 2005 Jun 28;44(25):9117-22. PMID:15966735
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