EC Number   |
General Information |
Reference |
|---|
    1.3.98.3 | more |
a mutant Rubrivivax gelatinosus deficient in the Cu2+-ATPase CopA accumulates coproporphyrinogen III, excess copper affects the synthesis of tetrapyrroles, affecting the heme and chlorophyll containing complexes |
726009 |
| 1.3.98.3 | physiological function |
addition of Lactococcus lactis membranes to heme-containing HemW triggers the release of heme from HemW in vitro. Role of HemW in heme trafficking |
724235 |
| 1.3.98.3 | physiological function |
catalyzes the decarboxylation of coproporphyrinogen III to form protoporphyrinogen IX in heme biosynthesis and is shared in chlorophyll biosynthesis in photosynthetic organisms |
713258 |
| 1.3.98.3 | physiological function |
coproporphyrinogen III is converted to protoporphyrinogen IX under anaerobiosis and low oxygen tension by the anaerobic coproporphyrinogen III oxidase HemN. The Cu+-ATPase CopA is not directly required for cytochrome c oxidase but is vital for copper tolerance. The physiological role of the copper P1B-type transporter CtpA, though homologous to CopA, differs from that of the effluxATPase CopA, because CtpA is dispensable for copper tolerance in contrast to CopA. HemN, a radical SAM and iron-sulfur containing protein, is a target enzyme in the tetrapyrrole biosynthesis pathway |
745799 |
| 1.3.98.3 | malfunction |
excess copper in the copA- mutant, deficient for Cu+-ATPase CopA via transposon mutagenesis, results in a substantial decrease of the cytochrome c oxidase and the photosystem under microaerobic and anaerobic conditions together with the extrusion of coproporphyrin III. Enzyme CopA is required for the activity of cuproproteins in the purple bacterium Rubrivivax gelatinosus. CopA is not directly required for cytochrome c oxidase activity but is vital for copper tolerance. The Cu+-ATPase CtpA is required only for the activity of cuproproteins in the purple bacterium Rubrivivax gelatinosus |
745799 |
| 1.3.98.3 | metabolism |
genes hemH and hemW (hemN) show conjectured functions in heme metabolism |
724235 |
| 1.3.98.3 | evolution |
HemW-like proteins form a distinct phylogenetic clade. It contains the four cysteine residues of the radical S-adenosyl-L-methionine enzyme motif of CPDH enzymes, structure comparisons, overview. The fourth cysteine residue of the Fe-S cluster motif of Escherichia coli HemN, CX3CX2CXC, is replaced by phenylalanine in HemW and related proteins |
724235 |
| 1.3.98.3 | evolution |
in eukaryotes and some bacteria, oxidative decarboxylation of coproporphyrinogen III is performed by the oxygen-dependent CPO HemF, EC 1.3.3.3. In most bacteria, the reaction is catalyzed by the oxygen-independent enzyme HemN. HemN belongs to the family of radical S-adenosyl-L-methionine enzymes. HemF and HemN are structurally completely unrelated and show different catalytic mechanisms, overview |
711348 |
| 1.3.98.3 | malfunction |
mutation in Arabidopsis thaliana CPO-coding gene AtHEMN1 adversely affects silique length, ovule number, and seed set. T-DNA insertions in gene HEMN1 cause seed sterility. Athemn1 mutant alleles are transmitted via both male and female gametes, but homozygous mutants are never recovered. Plants carrying Athemn1 mutant alleles show defects in gametophyte development, including nonviable pollen and embryo sacs with unfused polar nuclei. Improper differentiation of the central cell leads to defects in endosperm development. Consequently, embryo development is arrested at the globular stage. Reactive oxygen species Accumulates around the central cell in the female gametophytes. The mutant phenotype is completely rescued by transgenic expression of AtHEMN1. Blockage of tetrapyrrole biosynthesis in the AtHEMN1 mutant leads to increased reactive oxygen species accumulation in anthers and embryo sacs. The accumulated reactive oxygen species disrupt mitochondrial function by altering their membrane polarity in floral tissues. The AtHEMN1 mutation prevents the fusion of polar nuclei in the female gametophyte and affects endosperm proliferation. T-DNA insertion mutant lines of Arabidopsis thaliana show bushy habit and short siliques. Cell specification is not affected in Athemn1-1 mutant embryo sacs. Phenotype, overview |
746121 |
| 1.3.98.3 | malfunction |
oxidized coproporphyrinogen III accumulates in a hemN2- mutant in Rubrivirax gelatinosus only under oxygen limited conditions |
726009 |
