title: [New method for measuring the distances between the nitroxide spin label and paramagnetic metal ions in macromolecules].
abstract: A new method of estimation of the distance RLM between the nitroxide spin label (NSL) and the paramagnetic metal ions (PMI), such as Co2+, Ni2+, Cu2+, Mn2+, VO2+, Cr3+, Fe3+ is suggested. The influence of the longitudinal relaxation time T1 of the PMI on the line shape of the NSL at 77 degrees K has been studied. It was found that the efficiency of the dipole-dipole interaction between NSL and PMI depends strongly on the T1 value of the PMI. Measurements of the RLM for 4 spin-labelled proteins (haemoglobin, nitrogenase, cytochrome P450 and Ca2+-dependent ATPase) by three various methods have proved the correctness of the new method and also its simplicity.
mesh_terms: D002412:Cations; D002413:Cations, Divalent; D003497:Cyclic N-Oxides; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods; D008670:Metals / Q000032:analysis*; D011506:Proteins / Q000032:analysis*; D013113:Spin Labels
chemical_list: D002412:Cations; D002413:Cations, Divalent; D003497:Cyclic N-Oxides; D008670:Metals; D011506:Proteins; D013113:Spin Labels; C001803:tempol
vernacular_title: Novyĭ sposob izmereniia rasstoianiĭ mezhdu spinovoĭ metkoĭ i paramagnitnymi ionami metallov v makromolekulakh.