The effects of terminal electron acceptor and sodium azide on the Paracoccus denitrificans protein composition
| Authors | |
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| Year of publication | 2004 |
| Type | Article in Proceedings |
| Conference | Acta Universitatis Palackianae Olomucensis - Chemica 43S |
| MU Faculty or unit | |
| Citation | |
| Field | Biochemistry |
| Keywords | Paracoccus denitrificans; proteome analysis; terminal electron acceptor; azide |
| Description | Paracoccus denitrificans is a non-fermentative, facultatively autotrophic soil bacterium often studied in the field of bioenergetics, particularly due to resemblance of its aerobic respiratory chain to that of mitochondria. Also an aspect of a great nutritional adaptability was discovered, related to the ability of exploiting various electron donors and electron acceptors for maintenance and growth. To discuss mechanisms underlying regulation of gene expression by growth conditions, a high-throughput proteome mapping is one of the most effective tools to-date. For 2-D electrophoretic analysis of whole-cell extract and its membrane fraction, isoelectric focusation with immobilized pH gradients in the first dimension and SDS-PAGE in the second dimension were used. Using this approach, more than 800 protein spots of total cell extract and membrane fraction were detected in the range pI 3-10 and Mr 15-100 kDa. We compared complex protein composition of whole cells of P. denitrificans cultivated under aerobic and various anaerobic conditions (with nitrate, nitrite and nitrous oxide). We also investigated the effect of respiratory inhibitor azide on proteomic profiles of the cells grown aerobically and anaerobically with NO2-. The similar approach was applied also on membrane fractions of cells (grown on O2, O2+N3-, NO3-). The most distinct proteomic profile matches the growth on nitrous oxide; the probable reasons are discussed. The significant changes in protein composition of total cell lysates were caused also by azide. Popis výsledku (dříve anotace) v anglickém jazyce (rozsah pro RIV: max. 1000 znaků)ÚdajeAbout 50 protein spots have been submitted to the analysis by peptide mass fingerprinting using MALDI-TOF MS. However, the genome of P. denitrificans has not been completely sequenced yet and, currently, information about only 98+126 proteins is available from Swiss?Prot/TrEMBL database. Due to this fact, we were able to identify only 8 proteins up to-date. Among them, nitrite reductase and succinate dehydrogenase are key enzymes in P. denitrificans metabolism. Nitrite reductase is the second of four enzymes catalyzing the denitrification pathway in P. denitrificans, where NO3- is reduced via NO2-, NO, N2O to molecular nitrogen under anaerobic conditions. Succinate dehydrogenase, fumarate-producing enzyme in citrate cycle, was previously found to be very close to the bovine heart mitochondrial enzyme, having four subunits (64.9, 28.9, 13.4 and 12.5 kDa). Our ID corresponds with the 28.9 kDa FeS subunit. We also compared expression data of nitrite reductase obtained by proteome analysis with the measurement of nitrite reductase enzyme activity. These data were in a good agreement. The quantitative data and protein maps are kept in a database in PDQUEST format. The web-accessible proteome 2-D database has been established at http://www.mpiib-berlin.mpg.de/2D-PAGE. |
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