Full-text resources of PSJD and other databases are now available in the new Library of Science.
Visit https://bibliotekanauki.pl

Refine search results

Journals help

  1. 2 Acta Biochimica Polonica

Years help

  1. 2 2008

Authors help

  1. 2 Polcyn W.

Preferences help
Polish version English version Language
enabled [disable] Abstract
Number of results

Results found: 2

Number of results on page
first rewind previous Page / 1 next fast forward last

Search results

Search:
in the keywords:  membrane-bound nitrate reductase [EC 1.7.99.4]
help Sort By:

help Limit search:
first rewind previous Page / 1 next fast forward last
1
Content available remote

Nitrate-related down-regulation of respiratory nitrate reductase from Bradyrhizobium sp. (Lupinus)

100%
Polcyn W.
|
2008
|
vol. 55
|
issue 4
761-766
EN
Previously, we showed that anaerobic induction of respiratory nitrate reductase (NR) activity in Bradyrhizobium sp. (Lupinus) USDA 3045 is strongly enhanced by nitrate or nitrite through de novo synthesis. Here, multiple NR-active soluble forms, ranging from 75 kDa to 190 kDa, were observed under anaerobic conditions. Electrophoretic activity band patterns differed depending on the level and the type of the N oxyanion added. The intensity of the membrane-bound NR activity band of 230 kDa changed with time along with consumption of 2 mM nitrate. It was associated with a parallel 5-fold increase and then 2-fold reduction in the amount of membrane-bound NR protein. In contrast, on 4 mM nitrate, the level of NR protein was much more stable, apparently due to slower nitrate depletion. Moreover, in cells anaerobically grown without nitrate addition, a 42-kDa derivative of NR degradation was immunodetected, which was not observed if nitrate was present in the medium. These findings suggest that the amount of the respiratory NR protein could be negatively regulated by endogenous proteases in relation to the level of nitrate available. It seems, therefore, that multiple native forms might be not different isoenzymes but immature complexes or derivatives of the enzyme protein turnover. This report adds to a modest list of bacterial enzymes apparently regulated by proteolysis, such as GS, MurAA, EnvA, GdhA, and MetA.
2
Content available remote

Mass spectrometry identification of membrane-bound respiratory nitrate reductase from Bradyrhizobium sp. (Lupinus)

100%
Polcyn W.
|
2008
|
vol. 55
|
issue 4
753-760
EN
Respiratory nitrate reductase (NR) from Bradyrhizobium sp. (Lupinus) USDA 3045 has biochemical properties of the membrane-bound NR type. However, in the completely sequenced rhizobium genomes only genes for the periplasmic type of dissimilatory NR were found. Therefore purification and identification of the enzyme by tandem mass spectrometry (MS/MS) was undertaken. MS/MS spectra representing 149 unique tryptic peptides derived from purified 137-kDa subunit matched the NCBInr-deposited NarG sequences. MS/MS sequencing of two other SDS/PAGE bands (65- and 59-kDa) identified them as derivatives of the NarH-type protein. Applying additional validation criteria, 73% of the sequence of the NarG subunit (902 aa) and 52% of NarH sequence (266 aa) was assembled (UniProt KB acc. no. P85097 and P85098). This is the first unambiguous identification of an active NarGH-like NR in rhizobia. Moreover, arguments are provided here for the existence of a functional enzyme of this type also among other rhizobial species, basing on immunoblot screening and the presence of membrane-associated NR-active electrophoretic forms.
first rewind previous Page / 1 next fast forward last
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.