Title: water-NOE Description: It's a 2D heteronuclear (1H-15N) correlation spectrum of a HSQC-type to detect amide proton exchange rates and NOE's to water. You determine the magnetization exchange with water for the amide protons. To extract the true chemical echange rates you have to subtract the NOE contribution from them magnetization exchange rates. (---> Reference!) The NOE interaction can be measured in another experiment (water-ROE). ---> Pulse sequence and parameter file included (waterROE.c,waterROE.par.tar) In both cases (water-NOE and water-ROE) you acquire two experiments (interleaved) with the parameter watrsign set to 0 or 1. It watrsign = 0: --> you invert the water magnetization at the beginning of the pulse sequence to -Iz. In this case water-magnetization is anti- parallel to the amide proton magnetization (+Iz!). It watrsign = 1: --> you apply a 360 deg pulse on water, the water-magnetization is parallel to the amide proton magnetization! Look also in the figure, where red arrows indicate the water magnetization vector and black arrows the amide-proton magnetization vector! Spectrometer: Varian Unity Plus 600 MHz Pulse sequence: waterNOE.c Literature reference: S. Grzesiek & Ad Bax, J.Biomol.NMR 3, 627-638 (1993) Authors: Ronald Wiltscheck, Andrei T. Alexandrescu, Biozentrum, University of Basel Klingelbergstr. 70 CH-4056 Basel e-mail: wiltscheck@ubaclu.unibas.ch alexandrescu@ubaclu.unibas.ch www home page: http://nmr.bioz.unibas.ch phone: ++41-61/267-2091 fax: ++41-61/267-2190 Figure: water_NOE_ROE_pp.ps (postscript) water_NOE_ROE_pp.gif (Compuserve-GIF-format) water_NOE_ROE_pp.jpg (JPEG-format) Parameters: waterNOE.par.tar (Unix Tape Archive) Shaped pulses: halfshape.RF, watrshape.RF BMRB Pulse Sequence Accession Number: 45