Furthermore, this breakdown of homology modeling utility with low target-template identity challenges elucidation of structures for newly discovered proteins, several of which happen to fall into the twilight and midnight zones [26], [29], [30].
Moreover, membrane integral or associated proteins are challenging for structure elucidation by X-ray crystallography due to their lipophilic character.
The overall concentration of compounds produced by plant-associated bacteria in roots and the rhizosphere is usually low (usually < 10 μg/g), making the direct structure elucidation challenging.
Even with more sophisticated methods, such as the use of MS classifiers [52] and fragmentation patterns [53], structural elucidation is challenging.
Other substitution patterns are also possible, including N-acetylation and 3-O-sulfation of the glucosamine, as well as non-sulfated iduronate and β-D-glucuronate, and 2-O-sulfation of glucuronate, providing considerable sequence heterogeneity [9] and making the structural elucidation of heparin challenging.
These challenges notwithstanding, elucidation of epigenetic control of bone regulation may have translational implications; for example, some demethylating agents are already used to treat neoplastic disorders.
While much further progress is still needed in the area of lipid analytics, one of the biggest challenges is elucidation of biological phenomena behind the large amounts of lipidomics data currently available.
The natural movement patterns of bees have proven challenging to deduce, but their correct elucidation may permit us to make testable predictions concerning mutualisms, bee biology and parasitism, and the remarkably rapid radiation of angiosperms.
A number of epidemiological studies have demonstrated that osteoarthritis has a major genetic component, although elucidation of this has proven challenging [ 2].
Moreover, the common binder matrices are far from pure, making elucidation of the underlying emission mechanisms somewhat challenging, though nonetheless functional.
