Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P04179 (MnSOD)
 2,777 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Photosynthetic organisms are among the earliest life forms on earth and their biochemistry is strictly dependent on a wide range of inorganic nutrients owing to the use of metal cofactor-dependent enzymes in photosynthesis, respiration, inorganic nitrogen and sulfur assimilation. Chlamydomonas reinhardtii is a photosynthetic eukaryotic model organism for the study of trace metal homeostasis. Chlamydomonas spp. are widely distributed and can be found in soil, glaciers, acid mines and sewage ponds, suggesting that the genus has significant capacity for acclimation to micronutrient availability. Analysis of the draft genome indicates that metal homeostasis mechanisms in Chlamydomonas represent a blend of mechanisms operating in animals, plants and microbes. A combination of classical genetics, differential expression and genomic analysis has led to the identification of homologues of components known to operate in fungi and animals (e.g., Fox1, Ftr1, Fre1, Fer1, Ctr1/2) as well as novel molecules involved in copper and iron nutrition (Crr1, Fea1/2). Besides activating iron assimilation pathways, iron-deficient Chlamydomonas cells re-adjust metabolism by reducing light delivery to photosystem I (to avoid photo-oxidative damage resulting from compromised FeS clusters) and by modifying the ferredoxin profile (perhaps to accommodate preferential allocation of reducing equivalents). Up-regulation of a MnSOD isoform may compensate for loss of FeSOD. Ferritin could function to buffer the iron released from programmed degradation of iron-containing enzymes in the chloroplast. Some metabolic adjustments are made in anticipation of deficiency while others occur only with sustained or severe deficiency. Copper-deficient Chlamydomonas cells induce a copper assimilation pathway consisting of a cell surface reductase and a Cu(+) transporter (presumed CTR homologue). There are metabolic adaptations in addition: the synthesis of "back-up" enzymes for plastocyanin in photosynthesis and the ferroxidase in iron assimilation plus activation of alternative oxidase to handle the electron "overflow" resulting from reduced cytochrome oxidase function. Oxygen-dependent enzymes in the tetrapyrrole pathway (coproporphyrinogen oxidase and aerobic oxidative cyclase) are also increased in expression and activity by as much as 10-fold but the connection between copper nutrition and tetrapyrroles is not understood. The copper-deficiency responses are mediated by copper response elements that are defined by a GTAC core sequence and a novel metalloregulator, Crr1, which uses a zinc-dependent SBP domain to bind to the CuRE. The Chlamydomonas model is ideal for future investigation of nutritional manganese deficiency and selenoenzyme function. It is also suited for studies of trace nutrient interactions, nutrition-dependent metabolic changes, the relationship between photo-oxidative stress and metal homeostasis, and the important questions of differential allocation of limiting metal nutrients (e.g., to respiration vs. photosynthesis).
 ...
PMID:Between a rock and a hard place: trace element nutrition in Chlamydomonas. 1676 55

Fe deficiency is one of several abiotic stresses that impacts plant metabolism because of the loss of function of Fe-containing enzymes in chloroplasts and mitochondria, including cytochromes, FeS proteins, and Fe superoxide dismutase (FeSOD). Two pathways increase the capacity of the Chlamydomonas reinhardtii chloroplast to detoxify superoxide during Fe limitation stress. In one pathway, MSD3 is upregulated at the transcriptional level up to 10(3)-fold in response to Fe limitation, leading to synthesis of a previously undiscovered plastid-specific MnSOD whose identity we validated immunochemically. In a second pathway, the plastid FeSOD is preferentially retained over other abundant Fe proteins, heme-containing cytochrome f, diiron magnesium protoporphyrin monomethyl ester cyclase, and Fe2S2-containing ferredoxin, demonstrating prioritized allocation of Fe within the chloroplast. Maintenance of FeSOD occurs, after an initial phase of degradation, by de novo resynthesis in the absence of extracellular Fe, suggesting the operation of salvage mechanisms for intracellular recycling and reallocation.
 ...
PMID:Fe sparing and Fe recycling contribute to increased superoxide dismutase capacity in iron-starved Chlamydomonas reinhardtii. 2268 65

The present study provides data on the insertion of an extra copy of phytochelatin synthase (alr0975) in Anabaena sp. PCC 7120. The recombinant strain (AnFPN-pcs) compared to wild type showed approximately 22.3% increase in growth rate under UV-B, NaCl, heat, CuCl2, carbofuran, and CdCl2. It also registered 2.25-fold enhanced nitrogenase activity and 5-fold higher phytochelatin production. A comparison of the protein profile of wild type with the recombinant strain revealed that recombinant strain accumulated proteins belonging to the following categories: (i) detoxification (nutrient stress induced DNA binding protein, Mn-SOD, Alr0946 (CalA)), (ii) protein folding and modification (molecular chaperone DnaK, FKBP-type peptidyl-prolyl cis-trans isomerase), (iii) nucleotide and amino acid biosynthesis (dihydroorotase and Ketol-acid reductoisomerase), (iv) photosynthesis and respiration (coproporphyrinogen III oxidase, phycocyanin alpha chain, ferredoxin-NADP+ reductase), and (v) transport (sugar transport ATP-binding protein). Thus, it can be concluded that, above category proteins with their respective role in scavenging reactive oxygen species, proper folding of unfolded proteins, and protection of protein from degradation, sustained carbon fixation and energy pool and active transport of sugar together conceivably help the recombinant cyanobacterium (AnFPN-pcs) to cope with abiotic stress employed in the present study. Such recombinant strains have potential for future use as biofertilizer.
 ...
PMID:Overexpression of phytochelatin synthase (pcs) enhances abiotic stress tolerance by altering the proteome of transformed Anabaena sp. PCC 7120. 2800 Jan 19