During heme biosynthesis the oxygen-independent coproporphyrinogen III oxidase HemN catalyzes the oxidative decarboxylation of the two propionate side chains on rings A and B of coproporphyrinogen III to the corresponding vinyl groups to yield protoporphyrinogen IX. Here, the sequence of the two decarboxylation steps during HemN catalysis was investigated. A reaction intermediate of HemN activity was isolated by HPLC analysis and identified as monovinyltripropionic acid porphyrin by mass spectrometry. This monovinylic reaction intermediate exhibited identical chromatographic behavior during HPLC analysis as harderoporphyrin (3-vinyl-8,13,17-tripropionic acid-2,7,12,18-tetramethylporphyrin). Furthermore, HemN was able to utilize chemically synthesized harderoporphyrinogen as substrate and converted it to protoporphyrinogen IX. These results suggest that during HemN catalysis the propionate side chain of ring A of coproporphyrinogen III is decarboxylated prior to that of ring B.
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http://dx.doi.org/10.1515/BC.2010.006 | DOI Listing |
Plants (Basel)
December 2024
College of Plant Sciences, Jilin University, Changchun 130062, China.
Chloroplasts are not only places for photosynthesis, but also participate in plant immunity and are important targets of pathogens. Pathogens secrete chloroplast-targeted proteins (CTPs) that disrupt host immunity and promote infection. (Lib.
View Article and Find Full Text PDFJ Biol Chem
September 2024
Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil. Electronic address:
Monoxenous trypanosomatid Strigomonas culicis harbors an endosymbiotic bacterium, which enables the protozoa to survive without heme supplementation. The impact of HO resistance and symbiont elimination on intracellular heme and Fe availability was analyzed through a comparison of WT strain with both WT HO-resistant (WTR) and aposymbiotic (Apo) protozoa. The relative quantification of the heme biosynthetic pathway through label-free parallel reaction monitoring targeted mass spectrometry revealed that HO resistance does not influence the abundance of tryptic peptides.
View Article and Find Full Text PDFInt J Mol Sci
May 2024
College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China.
Heme biosynthesis is a highly conserved pathway from bacteria to higher animals. Heme, which serves as a prosthetic group for various enzymes involved in multiple biochemical processes, is essential in almost all species, making heme homeostasis vital for life. However, studies on the biological functions of heme in filamentous fungi are scarce.
View Article and Find Full Text PDFFront Microbiol
March 2024
Institute of Microbiology, University of Technical Engineering, Braunschweig, Germany.
Nature utilizes three distinct pathways to synthesize the essential enzyme cofactor heme. The coproporphyrin III-dependent pathway, predominantly present in , employs an oxygen-dependent coproporphyrinogen III oxidase (CgoX) that converts coproporphyrinogen III into coproporphyrin III. In this study, we report the bioinformatic-based identification of a gene called , encoding a putative oxygen-independent counterpart, which we propose to term CgoN, from () .
View Article and Find Full Text PDFmSphere
March 2024
Department of Biological Sciences, Clemson University, Clemson, South Carolina, USA.
Unlabelled: is an apicomplexan parasite that is the cause of toxoplasmosis, a potentially lethal disease for immunocompromised individuals. During infection, the parasites encounter various growth environments, such as hypoxia. Therefore, the metabolic enzymes in the parasites must adapt to such changes to fulfill their nutritional requirements.
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