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1o9i

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{{STRUCTURE_1o9i| PDB=1o9i | SCENE= }}
{{STRUCTURE_1o9i| PDB=1o9i | SCENE= }}
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'''CRYSTAL STRUCTURE OF THE Y42F MUTANT OF MANGANESE CATALASE FROM LACTOBACILLUS PLANTARUM AT 1.33A RESOLUTION'''
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===CRYSTAL STRUCTURE OF THE Y42F MUTANT OF MANGANESE CATALASE FROM LACTOBACILLUS PLANTARUM AT 1.33A RESOLUTION===
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==Overview==
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X-ray crystallography of the nonheme manganese catalase from Lactobacillus plantarum (LPC) [Barynin, V.V., Whittaker, M.M., Antonyuk, S.V., Lamzin, V.S., Harrison, P.M., Artymiuk, P.J. &amp; Whittaker, J.W. (2001) Structure9, 725-738] has revealed the structure of the dimanganese redox cluster together with its protein environment. The oxidized [Mn(III)Mn(III)] cluster is bridged by two solvent molecules (oxo and hydroxo, respectively) together with a micro 1,3 bridging glutamate carboxylate and is embedded in a web of hydrogen bonds involving an outer sphere tyrosine residue (Tyr42). A novel homologous expression system has been developed for production of active recombinant LPC and Tyr42 has been replaced by phenylalanine using site-directed mutagenesis. Spectroscopic and structural studies indicate that disruption of the hydrogen-bonded web significantly perturbs the active site in Y42F LPC, breaking one of the solvent bridges and generating an 'open' form of the dimanganese cluster. Two of the metal ligands adopt alternate conformations in the crystal structure, both conformers having a broken solvent bridge in the dimanganese core. The oxidized Y42F LPC exhibits strong optical absorption characteristic of high spin Mn(III) in low symmetry and lower coordination number. MCD and EPR measurements provide complementary information defining a ferromagnetically coupled electronic ground state for a cluster containing a single solvent bridge, in contrast to the diamagnetic ground state found for the native cluster containing a pair of solvent bridges. Y42F LPC has less than 5% of the catalase activity and much higher Km for H2O2 ( approximately 1.4 m) at neutral pH than WT LPC, although the activity is slightly restored at high pH where the cluster is converted to a diamagnetic form. These studies provide new insight into the contribution of the outer sphere tyrosine to the stability of the dimanganese cluster and the role of the solvent bridges in catalysis by dimanganese catalases.
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{{ABSTRACT_PUBMED_12631270}}
==About this Structure==
==About this Structure==
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[[Category: Oxidoreductase]]
[[Category: Oxidoreductase]]
[[Category: Preoxidase]]
[[Category: Preoxidase]]
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Jul 28 09:22:21 2008''

Revision as of 06:22, 28 July 2008

Image:1o9i.png

Template:STRUCTURE 1o9i

CRYSTAL STRUCTURE OF THE Y42F MUTANT OF MANGANESE CATALASE FROM LACTOBACILLUS PLANTARUM AT 1.33A RESOLUTION

Template:ABSTRACT PUBMED 12631270

About this Structure

1O9I is a Single protein structure of sequence from Lactobacillus plantarum. Full crystallographic information is available from OCA.

Reference

Outer sphere mutagenesis of Lactobacillus plantarum manganese catalase disrupts the cluster core. Mechanistic implications., Whittaker MM, Barynin VV, Igarashi T, Whittaker JW, Eur J Biochem. 2003 Mar;270(6):1102-16. PMID:12631270

Page seeded by OCA on Mon Jul 28 09:22:21 2008

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