Special structure feature identification

As well as these general motif databases, there are some more specialized sequence analysis tools for identifying particular structural or functional features. One well-studied example is that of coiled coils. The program COILS " allows one to compare a sequence against profiles derived from known parallel two-stranded coiled coils, to assess the likelihood that the query sequence is indeed a coiled coil. More involved analyses based on pairwise interactions have been developed, such as PAIRCOIL. Several families of coiled coils are actually well recognized by their PROSITE motifs. However, the leucine zipper PROSITE motif, L-X(6)-L-X(6)-L-X(6)-L, is poorly discriminating, and for this specific family of coiled coils, the program TRESPASSER provides a more refined identification... 

The main value of electron microscopy in recent years has been to allow morphological features to be determined for small objects and visualization of structures down to the molecular level. For non-biologists, however, it should be pointed out that most electron microscopes are operated in hard vacuum which can produce artifacts due to desiccation. In addition, it is often necessary to stain features with materials that are electron dense in order to provide sufficient contrast in the field under examination, and this can occasionally result in mis-identification of structures or additional artifacts being produced in the specimen. Electron microscopy is therefore a fascinating and specialized area with its own challenges. However, here is another scientific discipline that could benefit from the input of experienced particle size analysts in... 

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