biostudies-literaturePiszczek GIntramural NIH HHS332-42https://www.ebi.ac.uk/biostudies/studies/S-EPMC3058872biostudies-literatureUnknown507(2)Enzyme I(Ntr) is the first protein in the nitrogen phosphotransferase pathway. Using an array of biochemical and biophysical tools, we characterized the protein, compared its properties to that of EI of the carbohydrate PTS and, in addition, examined the effect of substitution of all nonexchangeable protons by deuterium (perdeuteration) on the properties of EI(Ntr). Notably, we find that the catalytic function (autophosphorylation and phosphotransfer to NPr) remains unperturbed while its stability is modulated by deuteration. In particular, the deuterated form exhibits a reduction of approximately 4°C in thermal stability, enhanced oligomerization propensity, as well as increased sensitivity to proteolysis in vitro. We investigated tertiary, secondary, and local structural changes, both inArchives of biochemistry and biophysicsDeuteration of Escherichia coli enzyme I(Ntr) alters its stability.PMC3058872Z99 HL999999Lee JCTjandra NLevine RLPiszczek GLee CRSeok YJPeterkofsky AfalseDeuteration of Escherichia coli enzyme I(Ntr) alters its stability.Enzyme I(Ntr) is the first protein in the nitrogen phosphotransferase pathway. Using an array of biochemical and biophysical tools, we characterized the protein, compared its properties to that of EI of the carbohydrate PTS and, in addition, examined the effect of substitution of all nonexchangeable protons by deuterium (perdeuteration) on the properties of EI(Ntr). Notably, we find that the catalytic function (autophosphorylation and phosphotransfer to NPr) remains unperturbed while its stability is modulated by deuteration. In particular, the deuterated form exhibits a reduction of approximately 4°C in thermal stability, enhanced oligomerization propensity, as well as increased sensitivity to proteolysis in vitro. We investigated tertiary, secondary, and local structural changes, both in2011-01-01T00:00:00Z2011 Mar2025-04-22T05:02:20.663Z2019-03-27T00:39:46ZS-EPMC30588722118580410.1016/j.abb.2010.12.022