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Merck

Probing three-dimensional structure of bovine serum albumin by chemical cross-linking and mass spectrometry.

Journal of the American Society for Mass Spectrometry (2004-07-28)
Bill X Huang, Hee-Yong Kim, Chhabil Dass
RESUMEN

Serum albumin is the principal transporter of fatty acids that are otherwise insoluble in circulating plasma. While the crystal structure of human serum albumin (HSA) as well as its binding with fatty acids has been characterized, the three dimensional structure of bovine serum albumin (BSA) has not been determined although both albumins share 76% sequence homology. In this study we used mass spectrometry coupled with chemical cross-linking, to probe the tertiary structure of BSA. BSA was modified with lysine specific cross-linkers, bis(sulfosuccinimidyl) suberate (BS(3)), disuccinimidyl suberate (DSS) or disuccinimidyl glutarate (DSG), digested with trypsin and analyzed by tandem mass spectrometry. With O-18 labeling during the digestion, through-space cross-linked peptides were readily identified in mass spectra by a characteristic 8 Da shift. From the cross-linked peptides identified in this study, we found that 12 pairs of lysine residues were separated within 20 A, while 5 pairs were spaced between 20 and 24 A. The spatial distance constraints generated from five K-K pairs in BSA were consistent with the corresponding distance obtained from the crystal structure of HSA, although only six equivalent K-K pairs could be compared. According to our data, the distance between K235 of IIA and K374 of IIB domain in BSA was farther by 7-11 A than that expected from the crystal structure of HSA, suggesting structural differences between BSA and HSA in this region. The distance constraints obtained for lysine residues using various cross-linkers should be valuable in assisting the determination of the 3-D structure of BSA.

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Roche
Seroalbúmina bovina, fracción V, sin ácidos grasos, 98.5% (electrophoresis), Fatty acids (total) ≤0.2 mg/g, Triglycerides (enzym.) free, Immunoglobulins not detectable, microbiological culture: suitable, USA origin
Roche
Bovine Serum Albumin Fraction V, heat shock, fatty acid free, from bovine serum
Roche
BSA Fraction V, ≥98.5%, Ash 1%, Heavy metals < 10 ppm, stem cell culture, Mycoplasma Negative, USA origin
Sigma-Aldrich
Seroalbúmina bovina solution, 35% in 0.85% sodium chloride, aseptically filled
Sigma-Aldrich
Albumin, Acetylated from bovine serum, protease free, for molecular biology
Sigma-Aldrich
Seroalbúmina bovina solution, 30%±2% in 0.85% sodium chloride, aseptically filled