2ia8

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spinqualitylabelsall models 2ia8, resolution 1.48Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

Kinetic and Crystallographic Studies of a Redesigned Manganese-Binding Site in Cytochrome c Peroxidase

Overview

Manganese peroxidase (MnP) from the white rot fungus Phanerochaete, chrysosporium contains a manganese-binding site that plays a critical role, in its function. Previously, a Mn(II)-binding site was designed into, cytochrome c peroxidase (CcP) based on sequence homology (Yeung et al. in, Chem. Biol. 4:215-222, 1997; Gengenbach et al. in Biochemistry, 38:11425-11432, 1999). Here, we report a redesign of this site based on, X-ray structural comparison of MnP and CcP. The variant, CcP(D37E, V45E, H181E), displays 2.5-fold higher catalytic efficiency (k (cat)/K (M)) than, the variant in the original design, mostly due to a stronger K (M) of 1.9, mM (vs. 4.1 mM). High-resolution X-ray crystal structures of a metal-free, form and a form with Co(II) at the designed Mn(II) site were also, obtained. The metal ion in the engineered metal-binding site overlays well, with Mn(II) bound in MnP, suggesting that this variant is the closest, structural model of the Mn(II)-binding site in MnP for which a crystal, structure exists. A major difference arises in the distances of the, ligands to the metal; the metal-ligand interactions in the CcP variant are, much weaker than the corresponding interactions in MnP, probably owing to, partial occupancy of metal ion at the designed site, difference in the, identity of metal ions (Co(II) rather than Mn(II)) and other interactions, in the second coordination sphere. These results indicate that the metal, ion, the ligands, and the environment around the metal-binding site play, important roles in tuning the structure and function of metalloenzymes.

About this Structure

2IA8 is a Single protein structure of sequence from Saccharomyces cerevisiae with as ligand. Active as Cytochrome-c peroxidase, with EC number 1.11.1.5 Full crystallographic information is available from OCA.

Reference

Kinetic and crystallographic studies of a redesigned manganese-binding site in cytochrome c peroxidase., Pfister TD, Mirarefi AY, Gengenbach AJ, Zhao X, Danstrom C, Conatser N, Gao YG, Robinson H, Zukoski CF, Wang AH, Lu Y, J Biol Inorg Chem. 2007 Jan;12(1):126-37. Epub 2006 Oct 5. PMID:17021923

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