Expression in Pichia Pastoris and Characterization by Circular Dichroism and NMR of Rhodostomin(2001)

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Rhodostomin(Rho) is a snake venom protein that is isolated from Calloselasma rhodostoma. Rho is a disintegrin that inhibits platelet aggregation by blocking the binding of fibrinogen to the integrin ƒÑIIbƒÒ3 of platelets. Rho produced in E. coli inhibited platelet aggregation with a KI of 263 nM. Although it is functional, Rho produced in E. coli is misfolded based on our 2D and 3D NMR studies. In order to correct the folding problem, Rho was expressed in Pichia pastoris(P. pastoris) . The recombinant Rho expressed in P. pastoris inhibited platelet aggregation with a resulting KI of 70 nM. This is the same potency as that of native Rho. CD analysis showed that the secondary structures of Rho are pH-independent and contain 3.5-7.9% ƒÑ-helix, 48.2-50.5% ƒÒ-structures, and 42.3-47% coil(Figure 1) . The sequential assignment and structure analysis of Rho were obtained using 2D and 3D 15N-edited NMR spectra(Figure 2) . These results provide the first direct evidence that highly disulfide-bonded disintegrin can be expressed in P. pastoris with the correct fold(1) . This evidence can serve as the basis for exploring the structure and function relationships as well as the dynamics of disintegrin and its variants.