title: Direct NMR resonance assignments of the active site histidine residue in Escherichia coli thioesterase I/protease I/lysophospholipase L1.
abstract: Owing to the hydrogen-bond interaction and rapid exchange rate with the bulk water, the transverse relaxation time for the N(delta1)-H proton of the catalytic histidine in Escherichia coli thioesterase I/protease I/lysophospholipase L1 (TEP-I) is rather short. Because of its catalytic importance, it is desirable to detect and assign this proton resonance. In this paper, we report the first direct NMR correlation between the short-lived N(delta1)-H proton and its covalently attached N(delta1)-nitrogen of the catalytic His157 residue in E. coli thioesterase/protease I. We have used gradient-enhanced jump-return spin-echo HMQC (GE-JR SE HMQC) to obtain a direct correlation between the short-lived N(delta1)-H proton and its covalently attached N(delta1)-nitrogen. The sensitivity of detection for the short-lived N(delta1)-H proton was enhanced substantially by improved water suppression, in particular, the suppression of radiation damping via pulsed field gradients.
authors.affiliation: Institute of Biomedical Sciences, Academia Sinica, Nankang, Taipei, Taiwan 11529, Republic of China. winston@ibms.sinica.edu.tw
authors.forename: Wen-Jin
authors.initials: WJ
authors.lastname: Wu
authors.forename: Sergiy I
authors.initials: SI
authors.lastname: Tyukhtenko
authors.forename: Tai-Huang
authors.initials: TH
authors.lastname: Huang
mesh_terms: D001224:Aspartic Acid / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D002384:Catalysis; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000378:metabolism*; D006639:Histidine / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008245:Lysophospholipase / Q000737:chemistry* / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D015394:Molecular Structure; D009154:Mutation / Q000235:genetics; D033903:Periplasmic Proteins / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D029968:Escherichia coli Proteins; D033903:Periplasmic Proteins; D001224:Aspartic Acid; D006639:Histidine; D008245:Lysophospholipase; C400724:tesA protein, E coli