Structure restraints

The oldest and most widely used structural restraints in NMR spectroscopy are distance restraints derived from NOE experiments [1]. Transient NOE, 2D NOESY and ROESY spectra provide valuable information for interatomic distances up to 5 A that will be discussed in the following. 

The ubiquitin backbone structure has been determined using dipolar couplings as the sole source of structural restraints in the work reported by Hus et al. [105]. The resulting structure is practically identical to the NMR structure calculated from NOE and other... 

The solution structures of 1 1 complex between paromomycin and gentamicin Cla and the A-site oligonucleotide have been solved at high resolution using heteronuclear NMR techniques These approaches require the preparation of uniformly labeled N- and C-RNA oligonucleotides via in vitro transcription with labeled nucleoside triphosphates. The use of RNAs labeled with NMR-active nuclei allows for the application of sophisticated heteronuclear NMR methods. These methods facilitate the assigmnent of NMR resonances and the acquisition of structural restraints for detailed structure determinations. 

The minor perturbation of the DNA structure caused by cis-platin may well not be detected in a cell which has a deficiency in the repair mechanism, whereas a normal cell might have a more selective repair mechanism. Whether this is the mechanism of action of the platinum anticancer drugs still has to be established, but it is the first model which satisfactorily accounts for all the known chemical and structural restraints. In addition, it suggests further modeling experiments with the more effective second generation drugs. 

Through-space (dipolar) and through-bond (contact) interactions can be employed to perform a focused study of the stracture of a paramagnetic metal-binding site in a protein, or to obtain additional structural restraints for determination of a full solution structure. This section is dedicated to the analysis of global molecular structure. Examples of focused studies of metal site structure are given in Section 4. 

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