Human Serum Albumin Recombinant HSA Is Structurally And Biochemically Equivalent To pHSA

Recombinant Human Serum Albumin HSA is structurally and biochemically equivalent to pHSA

Description

Healthgen Biotech recombinant human serum albumin is animal origin free, which effectively avoid any potential risk of animal contaminants, bacteria, prions, virus and contagious protein disease. The rice endosperm specific expression platform is easy to be large-scale. The rice endosperm has the protein body, which can keeps proteins stability and bioactivity. At present, the production capacity is almost 1000 kg / year.

OsrHSA Is Structurally and Biochemically Equivalent to pHSA.

The expressed OsrHSA has the same molecular mass, amino acid sequence, N- and C terminus, and melting point as pHSA. The circular dichroism (CD) spectrum of OsrHSA in the near- and far-UV region matched that of pHSA, indicating that both the secondary and tertiary structure of OsrHSA are identical to those of pHSA. Spectroscopic analysis further confirmed that OsrHSA has the same conformation as pHSA.

To characterize the structure of OsrHSA, an OsrHSA–myristic acid complex was crystallized, and the structure was solved by molecular replacement using the previously determined HSA structure at a refinement of 2.5 Å (PDB ID code 1BJ5), presenting a final R-free value of 0.303. A crystal of two independent molecules of OsrHSA was obtained in an asymmetric unit. The overall structure of OsrHSA is a heart shape formed by three helical domains, designated I, II, and III, and with myristic acids bound at the hydrophobic cavities. A superposition of all α-carbon atoms of the crystal structures of OsrHSA and pHSA resulted in a rmsd of 0.67 Å for PBD ID code 2I2Z and 0.69 Å for 1BJ5.

No obvious differences in main-chain conformations were identified between pHSA and OsrHSA, which demonstrates that OsrHSA in rice endosperm cells is folded into the identical structure as pHSA in blood plasma. As expected, 17 disulfide bonds were identified as genuine disulfide bonds, and a free cysteine (Cys) residue was observed at position 34. HSA is known to act as a carrier protein, mainly through two docking sites for drugs and 7–9 sites for fatty acids (27). Eight myristic acids were observed bound to the recombinant HAS molecule, and all fatty acid binding sites in OsrHSA were identified at the same locations as in pHSA. Two drugbinding sites found in pHSA were also present in OsrHSA. Site I is a hydrophobic cavity located in subdomain II, delineated by the residues F211, W214, A215, and L238. Two clusters of polar residues responsible for ligand interaction were populated by amino acids Y150, H242, R257, and K195, K199, R218, R222, respectively. Site II was another hydrophobic pocket in subdomain IIIA composed of L387, Y411, L453, V433, and L430. One polar region, made up of R410, K414, and S489, was found in this binding site. The structural topology of these binding sites in OsrHSA suggests that it can perform the same biological functions as pHSA.