Noesy [autosaved]

KNOWLEDGE

1. Noesy ( nuclear overhouser effect spectroscopy ) Submitted to- Dr. myank rashmi mam Submitted by- sarita Maurya(m. sc bioinformatics)

2. content NOE(Nuclear overhauser effect) NOESY( nucleae overhauser effect spectroscopy) NOESY experiment Properties of NOESY NOESY application 2D-NOESY spectra of small molecule 2D NMR Types of 2D NMR PRINCIPL

3. Noe (nuclear overhauser effect) The NOE is of great value in studying the molecular geometry of the compounds. It tell whether the two protons are in close proximity within the molecules or not. An important consequence of this effect is that the line intensities observed in the normal spectrum may not be the same as in the decoupled spectrum.

4. Difinition of noesy The NOESY is a 2D nmr spectroscopic method used to identify nuclear spins undergoing class-relaxation and to measure their cross-relaxation rates. NOESY is an important tool to identify stereochemistry of protein and other biomolecules in solution. NOESY is a two-dimensional NMR spectroscopy method.

5. Noesy experiment The NOESY experiment can also be performed in a one dimensional fashion by pre-selected nuclei giving a large , negative signal while neighboring nuclei are identified by weaker ,positive signal.this only reveals which peak have measurable NOEs to the resonance of interest but takes much less time than the full 2D experiment.

6. Properties of noesy Cross peak between protons which are in close spatial proximity. For short enough mixing times (small molecule 400-800ms, large molecule 100-200ms) the cross peak intensity is proportional to the cross relaxation rate and thus to r. For small molecule noe and chemical exchange will give cross of opposite sign and can be distinguished. As sequence is identical to DQF-COSY, coupling can cause artefacts in spectrum.

7. application One application of NOESY is in the study of large biomolecules such as in protein NMR, which can often be assigned using sequential walking.

8. 2d-noesy spectra 0f small molecules The noesy spectrum uses the nuclear overhauser effect(NOE) to provide information about which proton(typically) resonance are from protons which are close together in space. This is distinct from COSY-type spectra which use the J-coupling interation to report on which proton resonances are located on the same or adjacent carbon nuclei.

9. 2d nmr The first 2D experiment was proposed by jean jenner . 2D NMR is set of nuclear magnetic resonance spectroscopy methods which give data plotted in a space defined by to frequency axes rather than one. 2D NMR spectra provide more information about a molecule than one-dimensional NMR spectra. 1D=one time variable,one intensity variable 2D=two time variables, two time intensity variable..

10. Types of 2d nmr Homonuclear experiment: in this experiment we provide two frequency to same nuclei in sample. i.e.H -H Correlation spectroscopy (cosy)actually in it we basically see homonuclear connectivity between same nuclei. Hectronuclear experiment: in this experiment we provides two frequency to different nuclei in the sample.i.e . H-C Hectronuclear Correlation(HETCOR).

11. principle of 2d nmr 2D NMR is nuclear magnetic resonance spectroscopy in which we provide a 90 degree pulse to our sample which is placed in uniform magnetic field then we wait for (oms-5ms) depending upon the experiment type then again we provide again 90 degree pulse and this time we measure signal as FID. As a result we get two FID signals which are plotted with respect to time domain. To get a meaningful data, we apply fourier transform program on FIDs to get frequency.

12. Application of 2d nmr Two- dimensional NMR lead to the development of chemical shifts into two dimensional and to resolve overlap of resonance which enables the correlation of intracting nuclei to be determined. Two dimensional NMR can be applied to complex spectra which are difficult to analyzed by conventional methods. COSY identifies pair of protons which are coupled to each other. The HETCOR spectra used to detect directly bounded 13C-1H.

13. Limit of nmr Limited to measurement of nucleus with magnetic moment. Less sensitive than other spectroscopic and chromatographic analytical methods. No response in ionic state. Paramagnetic component broaden NMR lines which reduces NMR signal and sensitivity.

14. Thank you