Two-dimensional NMR Study of the Heme Active Site Structure of Chloroperoxidase

Abstract

The heme active site structure of chloroperoxidase (CPO), a glycoprotein that displays versatile catalytic activities isolated from the marine mold Caldariomyces fumago, has been characterized by two-dimensional NMR spectroscopic studies. All hyperfine shifted resonances from the heme pocket as well as resonances from catalytically relevant amino acid residues including the heme iron ligand

Characterization of Recombinant Chloroperoxidase, and F103A and C29H/C79H/C87H Mutants

“…(Satterlee, Erman et al 1983); The value of 4.76 ppm instead of the usual 4.81 ppm was selected to be consistent with previous experimental work on CPO (Wang, Tachikawa et al 2003). …”

“…2.8). In contrast, the proton NMR spectrum of the Wt CPO-CN adduct has pairwise signals because of the presence of two isozymes (Wang, Tachikawa et al 2003), which complicates spectral interpretation. The rCPO-CN adduct was in the ferric low spin state and provided relatively sharp NMR signals ( Fig.…”

“…heme iron (Sundaramoorthy, Terner et al 1995;Wang, Tachikawa et al 2003). This water molecule is displaced by the incoming H 2 O 2 during reactions.…”

“…Furthermore, the cleavage of H 2 O 2 could be facilitated by Glu183, His105, and Asp106 acting as a proton relay shuttle ( Fig. 1.6) (Pelletier, Altenbuchner et al 1995;Wang, Tachikawa et al 2003).…”

Tailoring Heme-Thiolate Proteins into Efficient Biocatalysts with High Specificity and Selectivity

“…The deprotonated Glu183 abstracts a proton from the substrate hydrogen peroxide, and then the formed hydroperoxo-anion binds to the heme iron, yielding a ferric-hydroperoxo species known as Compound 0. Glu183 then protonates the distal oxygen of Cpd 0 and the peroxide O-O is cleaved heterolytically to generate Cpd I and release a water molecule, similar to other peroxidase mechanisms (107,108). CPO is adept in catalyzing a number of chiral oxidations with high yields and high enantioselectivity, in addition to alkyne hydroxylation and heteroatom dealkylation (109)(110)(111)(112)(113)(114).…”