The serpins (serine proteinase inhibitors) are structurally similar but functionally diverse proteins that fold into a conserved structure and employ a unique suicide substrate-like inhibitory mechanism. Serpins like a-antitrypsin, a- antichymotrypsin, C1-inhibitors, antithrombin and plasminogen activator inhibitor-1, play absolutely critical role in the control of proteinases involved in the inflammatory, complement, coagulation and fibrinolytic pathways respectively, and are associated with diseases like emphysema/cirrhosis, angioedema, familial dementia, chronic obstructive bronchitis and thrombosis Serpins are delicately balanced to perform its function with many critical residues involved in maintaining metastability.  However due to its typical mechanism of inhibition, naturally occurring serpin variants produces conformational instability which consequently forms the basis of many pathological disorders.  Understanding the molecular basis of such defects is central to devising strategies for its cure.