Novel EPR signals associated with FeMoco centres of MoFe protein in MgADP-inhibited turnover of nitrogenase |
| |
Authors: | Maritano S Fairhurst S A Eady R R |
| |
Institution: | Department of Biological Chemistry, John Innes Centre, Colney, Norwich NR4 7UH, UK. |
| |
Abstract: | Two novel electron paramagnetic resonance (EPR) signals arising from the 1Mo-7Fe-9S-homocitrate] (FeMoco) centres of MoFe protein of Klebsiella pneumoniae nitrogenase (Kp1) were observed following turnover under MgATP-limited conditions. The combination of the nitrogenase Fe protein of Clostridium pasteurianum showed similar signals. The accumulation of MgADP under these conditions causes the normal EPR signal of dithionite-reduced Kp1 (with g=4.3, 3.6, 2.01) to be slowly converted to novel signals with g=4.74, 3.32, 2.00 and g=4.58, 3.50, 1.99. These signals do not form in incubation of protein mixtures containing only MgADP, thus they may be associated with trapped intermediates of the catalytic cycle. |
| |
Keywords: | |
本文献已被 PubMed 等数据库收录! |
|