The cyanobacterial protoporphyrinogen oxidase HemJ is a new b-type heme protein functionally coupled with coproporphyrinogen III oxidase
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F60076658%3A12310%2F18%3A43897310" target="_blank" >RIV/60076658:12310/18:43897310 - isvavai.cz</a>
Alternative codes found
RIV/61388971:_____/18:00492858
Result on the web
<a href="http://www.jbc.org/content/early/2018/06/20/jbc.RA118.003441.full.pdf" target="_blank" >http://www.jbc.org/content/early/2018/06/20/jbc.RA118.003441.full.pdf</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1074/jbc.RA118.003441" target="_blank" >10.1074/jbc.RA118.003441</a>
Alternative languages
Result language
angličtina
Original language name
The cyanobacterial protoporphyrinogen oxidase HemJ is a new b-type heme protein functionally coupled with coproporphyrinogen III oxidase
Original language description
Protoporphyrinogen IX oxidase (PPO), the last enzyme that is common to both chlorophyll and heme biosynthesis pathways, catalyzes the oxidation of protoporphyrinogen IX to protoporphyrin IX. PPO has several isoforms, including the oxygen-dependent HemY and an oxygen-independent enzyme, HemG. However, most cyanobacteria encode HemJ, the least characterized PPO form. We have characterized HemJ from the cyanobacterium Synechocystis sp. PCC 6803 (Synechocystis 6803) as a bona fide PPO; HemJ down-regulation resulted in accumulation of tetrapyrrole precursors and in the depletion of chlorophyll precursors. The expression of FLAG-tagged Synechocystis 6803 HemJ protein (HemJ.f) and affinity isolation of HemJ.f under native conditions revealed that it binds heme b. The most stable HemJ.f form was a dimer, and higher oligomeric forms were also observed. Using both oxygen and artificial electron acceptors, we detected no enzymatic activity with the purified HemJ.f, consistent with the hypothesis that the enzymatic mechanism for HemJ is distinct from those of other PPO isoforms. The heme absorption spectra and distant HemJ homology to several membrane oxidases indicated that the heme in HemJ is redox-active and involved in electron transfer. HemJ was conditionally complemented by another PPO, HemG from Escherichia coli. If grown photoautotrophically, the complemented strain accumulated tripropionic tetrapyrrole harderoporphyrin, suggesting a defect in enzymatic conversion of coproporphyrinogen III to protoporphyrinogen IX, catalyzed by coproporphyrinogen III oxidase (CPO). This observation supports the hypothesis that HemJ is functionally coupled with CPO and that this coupling is disrupted after replacement of HemJ by HemG.
Czech name
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Czech description
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Classification
Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
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OECD FORD branch
10608 - Biochemistry and molecular biology
Result continuities
Project
Result was created during the realization of more than one project. More information in the Projects tab.
Continuities
P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)<br>I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace
Others
Publication year
2018
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
Journal of Biological Chemistry
ISSN
0021-9258
e-ISSN
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Volume of the periodical
293
Issue of the periodical within the volume
32
Country of publishing house
US - UNITED STATES
Number of pages
11
Pages from-to
12394-12404
UT code for WoS article
000441408500007
EID of the result in the Scopus database
2-s2.0-85051355947