Interestingly, in addition to the polar residue insertion (K208N/G202E) and loop remodeling described above, the G266S mutation forms another new polar interaction, albeit with a crystallographic water and the side chain N210 that directly coordinates the Ca2+.
In addition, the signals derived from polar monomer inverse insertion were detected for the first time.
The method is based on the random generation of peptides and their selection on three main criteria: mean hydrophobicity and the presence of at least one polar residue; tilted insertion at the level of the acyl chains of lipids of a membrane; and conformational stability in that hydrophobic phase.
Genetic tools that utilize polar antibiotic cassette insertions limit mutant construction and complementation.
The experimental reduction in enzyme activity in the AKR1C2 variants F46Y and L172Q, as determined by Takahashi et al., is predicted to be due to increased instability in cofactor binding, caused by disruptions to the hydrogen bonds between NADP and AKR1C2, resulting from the insertion of polar residues into largely non-polar environments near the site of cofactor binding.
After plasma treatment, the contact angles are commonly lower than that obtained with the natural surface, because of the insertion of polar groups at the surface.
We have examined the effect of Si insertion at polar (1 0 0) and nonpolar (1 1 0) interfaces, and we have studied the insertion of Si (n-type) and Be (p-type) intralayers.
An analysis of the contributions of the individual residue types confirmed that hydrophobic residues are the main driving force behind membrane protein insertion, whereas polar, charged, and aromatic residues were found to be important for the correct orientation of the helix inside the membrane.
To assign function it is necessary to evaluate the possibility of polar effects of each insertion and to complement each disrupted gene with a WT copy; such efforts are beyond the scope of this initial study.
To rule out that the increased import length was caused by polar effects of the insertion of the resistance cassette on genes downstream of mutY, we next performed a functional complementation experiment by introducing into the chromosome of the mutY mutant an intact copy of mutY that was under the control of the strong urease promoter [19].
