Reactivity of Coproheme Decarboxylase with Monovinyl, Monopropionate Deuteroheme.

Coproheme decarboxylases (ChdCs) are terminal enzymes of the coproporphyrin-dependent heme biosynthetic pathway. In this reaction, two propionate groups are cleaved from the redox-active iron-containing substrate, coproheme, to form vinyl groups of the heme product. The two decarboxylation reactions proceed sequentially, and a redox-active three-propionate porphyrin, called monovinyl, monopropionate deuteroheme (MMD), is transiently formed as an intermediate.

Spectroscopic evidence of the effect of hydrogen peroxide excess on the coproheme decarboxylase from actinobacterial .

The actinobacterial coproheme decarboxylase from catalyzes the final reaction to generate heme via the "coproporphyrin-dependent" heme biosynthesis pathway in the presence of hydrogen peroxide. The enzyme has a high reactivity toward HO used for the catalytic reaction and in the presence of an excess of HO new species are generated. Resonance Raman data, together with electronic absorption spectroscopy and mass spectrometry, indicate that an excess of hydrogen peroxide for both the substrate (coproheme) and product (heme ) complexes of this enzyme causes a porphyrin hydroxylation of ring C or D, which is compatible with the formation of an iron chlorin-type heme species.

Initial Steps to Engineer Coproheme Decarboxylase to Obtain Stereospecific Monovinyl, Monopropionyl Deuterohemes.

The oxidative decarboxylation of coproheme to form heme by coproheme decarboxylase is a stereospecific two-step reaction. In the first step, the propionate at position two (p2) is cleaved off the pyrrole ring A to form a vinyl group at this position. Subsequently, the propionate at position four (p4) on pyrrole ring B is cleaved off and heme is formed.

An active site at work - the role of key residues in C. diphteriae coproheme decarboxylase.

Coproheme decarboxylases (ChdCs) are utilized by monoderm bacteria to produce heme b by a stepwise oxidative decarboxylation of the 2- and 4-propionate groups of iron coproporphyrin III (coproheme) to vinyl groups. This work compares the effect of hemin reconstitution versus the hydrogen peroxide-mediated conversion of coproheme to heme b in the actinobacterial ChdC from Corynebacterium diphtheriae (CdChdC) and selected variants. Both ferric and ferrous forms of wild-type (WT) CdChdC and its H118A, H118F, and A207E variants were characterized by resonance Raman and UV-vis spectroscopies.

Application of Recombinant Human scFv Antibody as a Powerful Tool to Monitor Nitrogen Fixing Biofertilizer in Rice and Legume.

is an endophytic bacterium under investigation as an efficient biofertilizer for sustainable legume-rice rotational cropping system. Monitoring and bio-imaging of this nitrogen fixing bacterium is essential for the study of plant-microbe evolution, soil microbiome, as well as quality control in organic farming. While phage display antibody technology has been widely used to generate recombinant antibody for myriad medical purposes, so far, this technology has been minimally applied in the agricultural sector.