The pharmacophore, as shown in Figure 4B revealed that these analogs mainly utilize the functional residues which are under structural constraints in all the DEAD box helicases.
We show that, in contrast to the surprising absence of sequence conservation, these nucleosomes are under strong structural constraints that are related to DNA curvature.
Additionally a synthesis based on LMI's under structural constraints is proposed.
For instance, the protein surface, which is occupied mostly by hydrophilic residues such as E, K, and N, is under less stringent constraints and thus tends to evolve faster than the protein core whose residues are under higher structural constraints and has a marked preponderance for hydrophobic amino acids (M, V, I, L, and F).
Conditions for re-fracturing have been derived and validated through the lateral constraint tests, which can be used to study load capacities and stabilities of surrounding rock in deep underground engineering under structural constraints formed by different supports.
Integral transmembrane proteins evolve under structural constraints that differ substantially from those of globular water-soluble proteins (30, 31).
A possible hypothesis based on these trends is that expensive amino acids are only used for specific structural or functional roles and are therefore conserved, while cheaper amino acids may be under weaker structural or functional constraints and more likely to be substituted.
An explanation of this incongruence might be in the differences between the predominantly circulating lineages of the UK and Belgium; these may differentially evolve and/or be under dissimilar structural or immunologic constraints.
Thus there seems to be a structural constraint in place.
Eukaryotic gene expression is often under the control of cooperatively acting transcription factors whose binding is limited by structural constraints.
