To determine the effect of mutation on a putative hinge region, I had mutated the single reside and determined the stability energy. The predicted value of stability appeared to be 2.83 Kcal/mol. Does stabilizing mutation have an effect on function ability of the protein?
The question is a bit vague. Are you talking about stability of the native state in terms of folding along an energy landscape, or during an enzymatic reaction along a reaction coordinate?
It depends on whether the function of the protein requires flexibility in the region you have stabilized. You may lock your hinge in a conformation which is favorable for binding, or you may lock it in an unfavorable configuration. Often stabilized enzymes can tolerate higher temperatures but are less active at lower temperatures. You will need to assay your specific system.
the question is very vague. The main point is the hinge. is it involved in the function? has a structural role linking domains? has a role in the overall dynamics of the protein? As you can see without these details it is difficult to give a reasonable suggestion.
If the hinge has a structural role, i.d. that binds two structural domains, it should be long enough (at least 5-10 residues) to be able to move or bend. This means that you must have some flexibility and the hinge is exposed to the solvent. In this case, any mutation hydrophilic-hydrophilic should not lead to large changes in energy, while if it induces hydrophilic-hydrophobic change can be critical. However it is not only the hydrophobicity to create problems but also the residue volumes. The hydrophobic ones have the largest volumes and this can induce structural constraints which, obviously, are lower with hydrophilics which are generally of small volume. In general, when you have an hydrophilic residue with small volume, you have an increase of local flexibility (that you can evaluate by means of a flexibility plot). The plot may be useful for a global evaluation of your hinge. As the hinge should be flexible but you find changes in energy this might mean that you have altered the structure of the organized part (globular). If your energetic evaluation is positive means that your change generates unfavorable structural perturbation..
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