LIFE SCIENCE

Detailed explanation-1: -Activation of 54-dependent nif gene transcription requires NifA, a conserved EBP that regulates genes necessary for the synthesis of molybdenum nitrogenase in proteobacteria. Activation of transcription by NifA is regulated in response to oxygen and fixed nitrogen.

Detailed explanation-2: -The nitrogenase complex is the primary enzyme that is encoded by the ‘Nif’ gene. It is responsible for converting atmospheric nitrogen to ammonia.

Detailed explanation-3: -In most bacteria, regulation of nif genes transcription is done by the nitrogen sensitive NifA protein. When there isn’t enough fixed nitrogen available for the organism’s use, NtrC triggers NifA expression, and NifA activates the rest of the nif genes.

Detailed explanation-4: -Transcription of nitrogen fixation genes (nif and fix genes) in these bacteria is induced primarily by low-oxygen conditions. Low-oxygen sensing and transmission of this signal to the level of nif and fix gene expression involve at least five regulatory proteins, FixL, FixJ, FixK, NifA, and RpoN (sigma 54).