Oligopeptides Oligosaccharides

Oligomers Oligonucleotides Oligopeptides Oligosaccharides 10 -10 2 Less than 10 Nucleotides a-Amino acids monosaccharides... 

Oligopeptide Oligosaccharide Oligonucleotide Amino acid Sugar Nucleic acid Builds/destroys Gatekeepers Gives orders... 

For situations where the product of the resonance frequency and the overall correlation time of a molecule approaches unity NOE effects are close to zero. Under these circumstances the proximity of spins in space can still be inspected in the rotating frame by the ROESY experiment. This is usually the case for small oligosaccharides and oligopeptides at higher magnetic fields. 

Oligopeptide- or oligosaccharide-conjugate materials are the typical examples for receptor-mimicking materials, the essential feature of which, of course, is biospecificity. In addition to these examples, a number of other processes and methodologies in ongoing biomaterials research are also based upon the concept of biospecificity some explicitly and others implicitly (See Table 1). Several of these examples will be reviewed in Sect. 5 under the title of biohybridized and biomimicking materials. 

The experiment is used to identify the subspectra of isolated spin system.s and is most often used for molecules which consist of rows or networks of similar fragments with no coupling interactions between them, e.g. oligosaccharides, oligopeptides or oligonucleotides. The experiment is usually combined with a COSY experiment, where it helps to overcome problems of overlapping cross peaks that can arise in the latter case. 

Figure 14.1. Construction of query saccharide structure for energy minimization with SWEET. Three-letter codes (IUBMB) for monosaccharides and amino acids are employed to construct oligosaccharide or oligopeptide chains. For monosaccharides, a- and p-anomers are prefixed with a and b, respectively. Pyranose and furanose rings are denoted as p and f, respectively.

As mentioned above, some naturally occurring cyclic hosts that possess molecular recognition capabilities were known before crown ethers (the first artificial host molecules) were discovered. For example, the cyclic oligopeptide valinomycin and the cyclic oligosaccharide cyclodextrin were found to bind to specific guest molecules. The chemical modification of cyclodextrin was particularly well-researched, and artificially modified cyclodextrins became one of the most important compoimds used in host-guest chemistry. 

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