The in-vivo identification of the MoFe protein (FeMo cofactor) of nitrogenase in Klebsiella pneumoniae and of the Mo-storage protein in Azotobacter vinelandii via the nuclear quadrupole interaction of [formula omitted

Abstract

The expression of the MoFe protein of nitrogenase in Klebsiella pneumoniae was identified in vivo via the nuclear quadrupole interaction (NQI) of 99 Mo(β −) 99Tc using perturbed angular correlations of γ-rays. The NQI parameters were: ω approx. 360 Mrad/s and η approx. 1. In addition, the NQI of the ‘Mo-storage protein’ in Azotobacter vinelandii cells which had been grown in the presence of NH 4 + (13 mM), i.e. under conditions of strict repression of nitrogenase synthesis, was determined: ω approx. 190 Mrad/s, η approx. 0.25. Under these conditions, the characteristic signal of the MoFe protein (FeMo cofactor) was absent.