instability index of expressed protein - (Sep/16/2013 )

Recentl I am busy expressing a membrane protein ,my expression vector is pET32a and pET28a,but it can`t be expressed.The instability index (II) is computed to be 55.64
This classifies the protein as unstable.I get confused,it really matters?


 

In general, predictive calculations can be helpful when figuring out the best strategy to express a protein, but there is still no substitute for experimental data.  So does it matter?  Not really.  What's more important in your case is probably, 1) where you are targeting the expression of this membrane protein and 2) the manner in which you determine protein expression levels.