Introduction: In innate immunity, the immune receptor FLAGELLIN SENSITIVE-2 is regarded as the best model to study the functional properties of other receptors. FLS2 is involved in Mitogen-activated protein kinase signaling pathways which have a crucial role in innate immunity. FLS2 is essential in the perception of flagellin. Furthermore, FLS2 is directed for degradation by the bacterial ubiquitin ligase AvrPtoB. Considering the importance of the FLS2 receptor, it is needed to the stability of this protein.
Methods: The Isoelectric pH of FLS2 was measured to evaluate protein stability. In addition, aliphatic index and GC percentage were also measured. The calculated instability index for the studied proteins showed that the proteins whose instability index is less than 40 are stable, otherwise they will be unstable. Therefore the FLS2 protein is regarded as one of the stable proteins. Proteins with a very high aliphatic index (above 100) may be stable in a very high- temperature range. Average total hydropathy (GRAVY) indicates the protein hydrophobicity index. If the GRAVY calculated for a protein is negative, it means that the protein is non-polar, and if it is positive, it is considered polar. The solubility of polar proteins is higher than the solubility of non-polar proteins in solvents. Against the special solvents of each protein, non-polar proteins accumulate in the middle and polar proteins accumulate in the outer part. Non-polar proteins can be used as targets to transfer the drug to the desired point, by adding a specific signal to the protein to transfer to the desired part and placing the target substance (drug) in the protein, this design is done.
Results: Our results showed that the instability index for FLS2 protein is less than 33.53. Because the aliphatic index of the studied protein is high than 100 (106.31), this protein is very stable against heat and can maintain its tertiary structure at high temperatures. Moreover, the percentage of GC (percentage of guanine and cytosine in the study sequence) was 46.6%. GC content analysis showed that genes with high GC content were more resistant to heat than genes with lower GC content. GRAVY calculated for FLS2 protein is negative (-0.016) and indicates its non-polarity.
Conclusion: The results showed that FLS2 protein is almost one of the stable proteins and non-polar proteins. The results that are investigated in this study, help researchers to better understand the FLS2 receptor and other immune receptors in detail.
Keywords: protein stability, FLS2, receptor,, Isoelectric point, Aliphatic chains, Relative volume of protein