Gradual exposure of cystine side-chain residues during urea denaturation of human serum albumin

1981 ◽  
Vol 46 (1) ◽  
pp. 48-51 ◽  
Author(s):  
Josef Chmelík ◽  
Jiří Kadleček ◽  
Vítěz Kalous
Keyword(s):  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Conformational Changes ◽  
Protein Molecule ◽  
Side Chain ◽  
Urea Denaturation ◽  
Catalytic Hydrogen ◽  
Denaturation Curve

Showing the accessibility of disulfide groups in the protein molecule, the polarographic catalytic hydrogen current (Brdicka current) was employed for the investigation of the urea denaturation of human serum albumin. The stepwise character of the denaturation curve was accounted for the gradual conformational changes of the protein molecule and related increasing accessibility of cystine side-chain residues.

Calcium ion binding to clinically relevant chemical modifications of human serum albumin

1995 ◽  
Vol 41 (11) ◽  
pp. 1654-1661 ◽  
Author(s):  
H Vorum ◽  
K Fisker ◽  
M Otagiri ◽  
A O Pedersen ◽  
U Kragh-Hansen
Keyword(s):  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Conformational Changes ◽  
Calcium Binding ◽  
Equilibrium Dialysis ◽  
Thiol Group ◽  
Protein Molecule ◽  
Penicillin G ◽  
Lysine Residues

Abstract Calcium binding to glycated, penicilloylated, acetylated, and normal defatted human serum albumin as well as to mercapt- and nonmercaptalbumin was studied by equilibrium dialysis of radioactive Ca2+. Binding was quantified by five Scatchard constants [ni = 1, (i = 1-4) and n5 = 10]. Glycation resulted in increased k1- and k2-values and unchanged k3-k5-values, whereas penicilloylation increased all five association constants. The increments were greater the more pronounced the modification, and the enhancements caused by penicilloylation were, for the same degree of modification, greater than those produced by glycation. In contrast, acetylation by acetylsalicylate did not affect calcium binding. Likewise, binding to mercapt- and nonmercaptalbumin was the same, a finding showing that the thiol group of cysteine 34 is not important for calcium binding. D-Glucose and penicillin G are known to react with lysine residues of albumin, and the enhancement of binding resulting from glycation or penicilloylation is probably brought about by unspecific electrostatic effects, possibly supplemented by conformational changes of the protein molecule. The relative importance of the three domains of human serum albumin for calcium binding is discussed.

Human Serum Albumin Conformational Changes as Induced by Tenoxicam and Modified by Simultaneous Diazepam Binding

1993 ◽  
Vol 45 (12) ◽  
pp. 1050-1053 ◽  
Author(s):  
F. BRÉE ◽  
S. URIEN ◽  
P. NGUYEN ◽  
J. P. TILLEMENT ◽  
A. STEINER ◽  
...  
Keyword(s):  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Conformational Changes

scholarly journals Systematic FTIR Spectroscopy Study of the Secondary Structure Changes in Human Serum Albumin under Various Denaturation Conditions

Biomolecules ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 359 ◽  
Author(s):  
Usoltsev ◽  
Sitnikova ◽  
Kajava ◽  
Uspenskaya
Keyword(s):  
Secondary Structure ◽  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Ftir Spectroscopy ◽  
Conformational Changes ◽  
Data Interpretation ◽  
Random Coil ◽  
Helical Conformation ◽  
Structure Changes

Human serum albumin (HSA) is the most abundant protein in blood plasma. HSA is involved in the transport of hormones, fatty acids, and some other compounds, maintenance of blood pH, osmotic pressure, and many other functions. Although this protein is well studied, data about its conformational changes upon different denaturation factors are fragmentary and sometimes contradictory. This is especially true for FTIR spectroscopy data interpretation. Here, the effect of various denaturing agents on the structural state of HSA by using FTIR spectroscopy in the aqueous solutions was systematically studied. Our data suggest that the second derivative deconvolution method provides the most consistent interpretation of the obtained IR spectra. The secondary structure changes of HSA were studied depending on the concentration of the denaturing agent during acid, alkaline, and thermal denaturation. In general, the denaturation of HSA in different conditions is accompanied by a decrease in α-helical conformation and an increase in random coil conformation and the intermolecular β-strands. Meantime, some variation in the conformational changes depending on the type of the denaturation agent were also observed. The increase of β-structural conformation suggests that HSA may form amyloid-like aggregates upon the denaturation.

Kinetic Studies of Copper(II)-exchange from L-Histidine to Human Serum Albumin and Diglycyl-L-histidine, a Peptide Mimicking the Copper(II)-transport Site of Albumin

1975 ◽  
Vol 53 (5) ◽  
pp. 710-715 ◽  
Author(s):  
Show-Jy Lau ◽  
Bibudhendra Sarkar
Keyword(s):  
Human Serum Albumin ◽  
Serum Albumin ◽  
Exchange Rates ◽  
Human Serum ◽  
Kinetic Studies ◽  
Side Chain ◽  
Exchange Reactions ◽  
Equilibrium Study ◽  
Rate Determining Step ◽  
The Difference

The Cu(II)-exchange reactions of L-histidine with human serum albumin and diglycyl-L-histidine were studied at pH 7.53 in 0.1 MN-ethylmorpholine–HCl buffer. The exchange rates from L-histidine to albumin and peptide were determined as 0.67 and 0.42 s−1 respectively. Those from albumin and peptide to L-histidine were obtained as 0.04 and 0.07 s−1 respectively. This result is in accord with the earlier observations of the equilibrium study that the peptide has about half the Cu(II)-binding affinity as compared to albumin. The difference in the Cu(II)-exchange rates of albumin and peptide may reflect the influence of either the COOH-terminal free carboxyl group of the peptide or the side-chain residues of the Cu(II)-binding site in the native protein or both. An exchange mechanism is proposed in which the ternary complexes are shown to play the important role in the rate-determining step in the Cu(II)-exchange between a macromolecule and a small substance.

scholarly journals Probing conformational changes of human serum albumin due to unsaturated fatty acid binding by chemical cross-linking and mass spectrometry

2005 ◽  
Vol 387 (3) ◽  
pp. 695-702 ◽  
Author(s):  
Bill X. HUANG ◽  
Chhabil DASS ◽  
Hee-Yong KIM
Keyword(s):  
Mass Spectrometry ◽  
Fatty Acids ◽  
Fatty Acid ◽  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Conformational Changes ◽  
Cross Linking ◽  
X Ray ◽  
Chemical Cross Linking

Mass spectrometry with chemical cross-linking was used to probe the conformational changes of HSA (human serum albumin) in solution on interaction with monounsaturated OA (oleic acid) or polyunsaturated AA (arachidonic acid) or DHA (docosahexaenoic acid). Fatty acid-free or -bound HSA was modified with lysine-specific cross-linkers and digested with trypsin. Cross-linked peptides were analysed by nano-electrospray ionization MS to localize the sites of cross-linking. Our data indicated that a local conformational change involving movement of the side chains of Lys-402 of subdomain IIIA or Lys-541 of subdomain IIIB occurred upon binding of all three fatty acids. Our data also indicated that the side chains of Lys-205 (IIA) and Lys-466 (IIIA) moved closer towards each other upon binding AA or DHA, but not OA, suggesting that the conformations of HSA when bound to mono- and poly-unsaturated fatty acids are distinctively different. While these observations agreed with previous X-ray crystallographic studies, the distances between ε-amino groups of most cross-linked lysine pairs were shorter than the crystal structure predicted, possibly reflecting a discrepancy between the solution and crystal structures. This method can serve as a useful complement to X-ray crystallography, particularly in probing the structure of a protein in solution.

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