Introduction of a mutation in the shutter region of antithrombin (Phe77 to Leu) increases affinity for heparin and decreases thermal stability

Results indicate that the Phe77 to Leu mutation in the shutter region of the serine proteinase inhibitor, antithrombin, results in conformational changes around the D-helix top of the inhibitor involving arginine 132 and 133 residues, which mediate antithrombin/heparin interactions.