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- Lindblad, A, et al.
(författare)
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Identification and sequence of a nifJ-like gene in Rhodospirillum rubrum : partial characterization of a mutant unaffected in nitrogen fixation
- 1996
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Ingår i: Molecular Microbiology. - : Wiley. - 0950-382X .- 1365-2958. ; 20:3, s. 559-568
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Tidskriftsartikel (refereegranskat)abstract
- A nifJ-like gene was identified in the photosynthetic purple non-sulphur bacterium Rhodospirillum rubrum. A DNA segment hybridizing to Klebsiella pneumoniae nifJ was isolated, the gene was inactivated, and a mutant strain, SNJ-1, was constructed by allele replacement. The mutation was confirmed by DNA sequencing. Northern blotting and by the lack of pyruvate oxidoreductase activity. This is the first report of a nifJ-like gene in photosynthetic bacteria. Unexpectedly, SNJ-1 was capable of nitrogen fixation, and growth was similar to the wild-type strain under all conditions investigated. Therefore, this is also the first demonstration that a nifJ homologue, when present, is not essential for nitrogen fixation in a diazotroph. The nifJ-like gene was sequenced and found to have considerable similarity to published nifJ gene sequences from other organisms. By primer extension, the initiation site for transcription was located, and a typical sigma 54 promoter sequence was identified.
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- Mäkinen, Taija, et al.
(författare)
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Differential binding of vascular endothelial growth factor B splice and proteolytic isoforms to neuropilin-1.
- 1999
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Ingår i: Journal of Biological Chemistry. - : Elsevier BV. - 0021-9258 .- 1083-351X. ; 274:30
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Tidskriftsartikel (refereegranskat)abstract
- Vascular endothelial growth factor B (VEGF-B) is expressed in various tissues, especially strongly in the heart, and binds selectively to one of the VEGF receptors, VEGFR-1. The two splice isoforms, VEGF-B(167) and VEGF-B(186), have identical NH(2)-terminal cystine knot growth factor domains but differ in their COOH-terminal domains which give these forms their distinct biochemical properties. In this study, we show that both splice isoforms of VEGF-B bind specifically to Neuropilin-1 (NRP1), a receptor for collapsins/semaphorins and for the VEGF(165) isoform. The NRP1 binding of VEGF-B could be competed by an excess of VEGF(165). The binding of VEGF-B(167) was mediated by the heparin binding domain, whereas the binding of VEGF-B(186) to NRP1 was regulated by exposure of a short COOH-terminal proline-rich peptide upon its proteolytic processing. In immunohistochemistry, NRP1 distribution was found to be overlapping or adjacent to known sites of VEGF-B expression in several tissues, in particular in the developing heart, suggesting the involvement of VEGF-B in NRP1-mediated signaling.
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