Hi Fereshteh, how are you defining "rigidity" of enzyme structures? Are you using DSC?

This is a very interesting question. I wanna know more, if you have some papers it will be grate.

Regards,

Maurizio

Hi Steingrimur. I define rigidity as stability against temperature( in my mean in this question). No I do fluorescent Quenching

Hi Fereshteh, are you defining "rigidity" as enzyme activity with increasing T? Or the unfolding Tm of the enzyme using DSC?

What do you mean that you do fluorescence quenching?

If you define rigidity like a protein with low plasticity or something similar, consider lipase B from Candida antartica... several disulfide bonds, in addition to a lid, I mean, it could be present a lot of problems with chemical hindrance or low motion of the catalytic pocket, but in fact, this is the best lipase (at least, if we talk at industrial scale).

Dear Steingrimur. mutant enzyme is more rigid ( I do fluorescent Quenching with acrylamide). also it has more stability against temperature. surprisingly it shows more activity. as most literature, when rigidity increase, enzyme activity decrease.

Hi Fereshteh, I am not familiar with the techniques that you are using. Can you describe them or give references?   

Hi dear Steingrimur. sorry for delay, do u know about stern-volmer equation. fluorescent quenching show flexibility of protein by increasing concentration of quencher like Acryleamid. after measuring intensity of fluorescent in different concentration of acrylamide for protein, we draw Line graph using stern-volmer equation. slope of line shows flexibility of protein. if I explain unclearly, I can send for u one article about that 

Hi Fereshteh, (text removed).

Steingrimur

yes Dear

Hi Fereshteh. You have to help me out here.

How do use  the Stern-Volmer acrylamide quenching method to determine  protein rigidity?