NifBderived

NifBderived is a term used in molecular biology and biochemistry to describe proteins, domains, or engineered constructs that originate from or are derived from the NifB enzyme. NifB is a radical S-adenosylmethionine (SAM) enzyme central to the biosynthesis of the nitrogenase FeMo-cofactor, the metal center required for biological nitrogen fixation. NifB-derived proteins thus encompass natural NifB homologs with substantial sequence divergence as well as designed variants created through truncation, domain swapping, site-directed mutagenesis, or directed evolution.

These derivatives are primarily studied for their roles in cofactor assembly and for mapping the contribution of individual motifs and domains to Fe-S cluster assembly and SAM chemistry. They are not intended to replace native NifB function in organisms; many derivatives are catalytically compromised or inactive in vivo but can retain partial activity in vitro.

Structural features of NifB-derived variants often reflect their origin from radical SAM enzymes. Many retain cysteine-rich motifs that coordinate Fe-S clusters and participate in SAM-dependent chemistry, though some derivatives have altered or removed these motifs. Some constructs preserve the two [Fe4S4] clusters associated with NifB, while others are truncated to examine the minimal regions required for specific assembly steps. The exact structure–function relationships depend on the specific derivative and experimental design.

Research and applications: NifB-derived constructs are used to probe the sequence of events in FeMo-cofactor biosynthesis, test hypotheses about domain function, and explore simplified or synthetic pathways for nitrogenase cofactors in heterologous systems. These studies advance understanding of nitrogen fixation and may inform future bioengineering efforts for sustainable ammonia production.

See also: Nitrogenase, FeMo-cofactor, NifB, radical SAM enzymes, protein engineering.