Relationship between stability and flexibility in the most flexible region of Photinus pyralis luciferase

The role of proline substitutions within flexible regions on thermostability of luciferase

“…For example, MD simulation and FRODA indicate that the Fragment 487-495 is one of the most flexible regions while B-FITTER fails to capture this information. Interestingly, analysis of B-factor has also been used to determine the most flexible region of P. pyralis luciferase by Zahra Amini-Bayst et al [36]. As similar as the results of our study, B-factor analysis in their study revealed that 473-477 region has high density of highest B-factor amino acids and did not show any evidence that Fragment 487-495 is a flexible region.…”

“…Zahra AminiBayat et al attempted to decrease this repulsion to rigidify this region through mutating ASP 476 to ASN. However, the D476N variant did not show any significant changes of thermostability and flexibility [36]. In our study, ASP 476 was mutated to a rigid residue, proline to decrease the flexibility of this region.…”

Electron transfer with myoglobin in free and strongly confined regimes: disclosing diverse mechanistic role of the Fe-coordinated water by temperature- and pressure-assisted voltammetric studies

“…The difference of 4.5 kJ mol −1 is close by the order of magnitude to the difference between the values of DH Exp a for freely diffusing and strongly confined Mb, 2.2 and 6.2 kJ mol −1 , respectively, if the values for free Mb in the presence of 2 M TMAO and in the absence of the extra additive are considered. As already mentioned above, the increase of DH Exp a in the sequence of 2 M urea > No additive > 2 M TMAO (opposite to the order for k 0 Exp ) could be expected at the cost of the additional contribution of DH Conf a (see equation (10)), since the conformational flexibility of the Mb interior should increase in this sequence causing gradual decrease of ν eff [80][81][82]. Finally, based on the abovementioned estimates of the inner-sphere contribution to DH Ã a , we estimated respective contributions to λ 0 .…”

“…It is well known that additives of urea cause proteins' thermodynamic destabilization [73,79], whereas TMAO, in general, efficiently stabilizes proteins [73,79]. In numerous publications, it has been demonstrated that the trends of proteins' stabilization/destabilization generally are accompanied with the decrease/increase of a fluctuational flexibility of proteins, such that the total unfolding (lack of secondary and tertiary structures) matches the maximal flexibility [73,[80][81][82]. Furthermore, it has been well established that Mb, in general, is a rather flexible protein that is required for the realization of its function − ligand binding/release through the "gating" motion of the protein matrix throughout the region of the "ligand channel" [32][33][34][44][45][46][47][48].…”

Delicate balance of electrostatic interactions and disulfide bridges in thermostability of firefly luciferase

“…The purity of the eluted proteins was visualized by SDS-PAGE and their concentrations were calculated by Bradford assay [19]. The activity of mutant proteins was assessed by the addition of luciferin and Mg 2+ -ATP in each step of purification [20].…”