Abstract
The secondary structure of a new type of recombinant RGD-hirudin, which has the activities of anti-thrombin and anti-platelet aggregation, has been studied by Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy and circular dichroism (CD) methods. The distribution of various secondary structure elements was determined using only a very small amount of sample protein. It was found that the recombinant RGD-hirudin contains about 26% extended chain, 21% β-turn and 53% unordered structure, leaving no α-helix. The results showed that the regular secondary structure of recombinant RGD-hirudin is increased compared with wild-type hirudin. The RGD segment that is located at the end of a long arm of a β-sheet is thought to play an important role in the additional function of anti-platelet aggregation. Throughout the experiments, FT-IR, Raman spectroscopy and CD generated mutually reinforcing results.
Keywords: Recombinant RGD-hirudin, FT-IR, Raman spectroscopy, CD, secondary structure