NifH gene

K. Haukka, K. Lindstrom, and P. J. Young, Three phylogenetic groups of nodA and nifH genes in Sinorhizobium and Mesorhizobium isolates from leguminous trees... 

The Fe protein contains two identical subunits of M.W.== 30,000 which are products of the nifH gene(12). A single Fe4S4 center is present in the protein and appears to be bound between the subunits.(12a) The Fe protein is reducible by cellular reductants such as flavodoxln or ferredoxin or artificial... 

The assembly of the molybdenum nitrogenase Fe protein involves the nifH gene and at least the nifS, nifU, and niJM gene prodncts that are implicated in the [4Fe 4S] cluster assembly, while the assembly of MoFe protein requires at least 15 nif gene products and involves the biosynthesis of FeMo cofactor and FeMo cofactor deficient MoFe protein in separate pathways and the insertion of FeMo cofactor into the MoFe protein. 

NifH gene diversity studies reported a significant fraction of nifH sequences clustered with proteobacteria rather than cyanobacteria, thus suggesting that components of this clade also are involved with N2 fixation (Falc6n et al., 2004 Langlois et al., 2005 Zehr et al, 2001) (Table 4.1). Bird et al. (2004) examined the distribution of an uncultured diazotrophic y-proteobacteria most closely related to Vibrio natriegens and Azotobacter vinelandii in the Arabian Sea. While they found it most... 

Mehta, M. P., Butterfield, D. A., and Baross, J. A. (2003). Phylogenetic diversity of nitrogenase (nifH) genes in deep-sea and hydrothermal vent environments of the Juan de Fuca ridge. Appl. Environ. 

Zehr, J. P., Mellon, M. T., and Zani, S. (1998). New nitrogen-fixing microorganisms detected in oligotrophic oceans by the amplification of nitrogenase (nifH) genes. Appl. Environ. Microbiol. 64, 3444-3450. 

Braun, S. T., Proctor, L. M., et al. (1999). Molecular evidence for zooplankton-associated nitrogenfixing anaerobes based on amplification of the nifH gene. FEMS Microbiol. Ecol. 28, 2Ti—219. 

Ben-Porath J and Zehr JP. (1994). Detection and characterization of cyanobacterial nifH genes. Appl. Environ. Microbiol. 60, 880-887. 

Poly E, Mmuozier LJ, Bally R (2001) Improvement in the RFLP procedure for studying the diversity of nifH genes in cmnmunities of nitrogtai fixers in soil. Res Microbiol 152 95—103... 

---