Anabaena variabilis ATCC 29413 is a heterotrophic, nitrogen-fixing cyanobacterium containing both a Mo-dependent nitrogenase encoded by the nif genes and V-dependent nitrogenase encoded by the vnf genes. The nifB, nifS, and nifU genes of A. variabilis were cloned, mapped, and partially sequenced. The fdxN gene was between nifB and nifS. Growth and acetylene reduction assays using wild-type and mutant strains indicated that the nifB product (NifB) was required for nitrogen fixation not only by the enzyme encoded by the nif genes but also by the enzyme encoded by the vnf genes. Neither NifS nor NifU was essential for nitrogen fixation in A. variabilis.
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http://dx.doi.org/10.1128/jb.177.6.1570-1575.1995 | DOI Listing |
Trends Biotechnol
January 2025
College of Biological Sciences, China Agricultural University, Beijing 100193, China. Electronic address:
Engineering nitrogen fixation in cereals could reduce usage of chemical nitrogen fertilizers. Here, a nitrogenase biosynthesis pathway comprising 13 genes (nifB nifH nifD nifK nifE nifN nifX hesA nifV nifS nifU groES groEL) was introduced into rice by transforming multigene vectors and subsequently by sexual crossing between transgenic rice plants. Genome sequencing analysis revealed that 13 nif genes in F hybrid rice lines L12-13 and L8-17 were inserted at two loci on rice chromosome 1.
View Article and Find Full Text PDFPlant Cell Physiol
June 2024
Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601 Japan.
In the genome of the heterocystous cyanobacterium Calothrix sp. NIES-4101 (NIES-4101), the four genes essential for nitrogen fixation (nifB, nifH, nifD and nifK) are highly fragmented into 13 parts in a 350-kb chromosomal region, and four of these parts are encoded in the reverse strand. Such a complex fragmentation feature makes it difficult to restore the intact nifBHDK genes by the excision mechanism found in the nifD gene of the Anabaena sp.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
October 2023
Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697-3900.
Nitrogenase is an active target of heterologous expression because of its importance for areas related to agronomy, energy, and environment. One major hurdle for expressing an active Mo-nitrogenase in is to generate the complex metalloclusters (P- and M-clusters) within this enzyme, which involves some highly unique bioinorganic chemistry/metalloenzyme biochemistry that is not generally dealt with in the heterologous expression of proteins via synthetic biology; in particular, the heterologous synthesis of the homometallic P-cluster ([FeS]) and M-cluster core (or L-cluster; [FeSC]) on their respective protein scaffolds, which represents two crucial checkpoints along the biosynthetic pathway of a complete nitrogenase, has yet to be demonstrated by biochemical and spectroscopic analyses of purified metalloproteins. Here, we report the heterologous formation of a P-cluster-containing NifDK protein upon coexpression of , , , and genes, and that of an L-cluster-containing NifB protein upon coexpression of , and genes alongside the gene, in .
View Article and Find Full Text PDFFront Microbiol
March 2023
State Key Laboratory for Agrobiotechnology and College of Biological Sciences, China Agricultural University, Beijing, China.
Nitrogenase in some bacteria and archaea catalyzes conversion of N to ammonia. To reconstitute a nitrogenase biosynthetic pathway in a eukaryotic host is still a challenge, since synthesis of nitrogenase requires a large number of (trogen ixation) genes. Viral 2A peptide mediated "cleavage" of polyprotein is one of strategies for multigene co-expression.
View Article and Find Full Text PDFmBio
June 2022
Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Pozuelo de Alarcón, Madrid, Spain.
Engineering plants to synthesize nitrogenase and assimilate atmospheric N will reduce crop dependency on industrial N fertilizers. This technology can be achieved by expressing prokaryotic nitrogen fixation gene products for the assembly of a functional nitrogenase in plants. NifB is a critical nitrogenase component since it catalyzes the first committed step in the biosynthesis of all types of nitrogenase active-site cofactors.
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