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Title: Abacavir and warfarin modulate allosterically kinetics of NO dissociation from ferrous nitrosylated human serum heme-albumin

Abstract

Human serum albumin (HSA) participates to heme scavenging, in turn HSA-heme binds gaseous diatomic ligands at the heme-Fe-atom. Here, the effect of abacavir and warfarin on denitrosylation kinetics of HSA-heme-Fe(II)-NO (i.e., k{sub off}) is reported. In the absence of drugs, the value of k{sub off} is (1.3 {+-} 0.2) x 10{sup -4} s{sup -1}. Abacavir and warfarin facilitate NO dissociation from HSA-heme-Fe(II)-NO, the k{sub off} value increases to (8.6 {+-} 0.9) x 10{sup -4} s{sup -1}. From the dependence of k{sub off} on the drug concentration, values of the dissociation equilibrium constant for the abacavir and warfarin binding to HSA-heme-Fe(II)-NO (i.e., K = (1.2 {+-} 0.2) x 10{sup -3} M and (6.2 {+-} 0.7) x 10{sup -5} M, respectively) were determined. The increase of k{sub off} values reflects the stabilization of the basic form of HSA-heme-Fe by ligands (e.g., abacavir and warfarin) that bind to Sudlow's site I. This event parallels the stabilization of the six-coordinate derivative of the HSA-heme-Fe(II)-NO atom. Present data highlight the allosteric modulation of HSA-heme-Fe(II) reactivity by heterotropic effectors.

Authors:
 [1];  [2];  [1];  [3];  [4];  [5]
  1. Department of Biology and Interdepartmental Laboratory for Electron Microscopy, University 'Roma Tre', Viale Guglielmo Marconi 446, I-00146 Roma (Italy)
  2. (Italy), E-mail: ascenzi@uniroma3.it
  3. (Italy)
  4. Department of Experimental Medicine and Biochemical Sciences, University of Roma 'Tor Vergata', Via Montpellier 1, I-00133 Roma (Italy)
  5. Department of Structural and Functional Biology, and Center of Neuroscience, University of Insubria, Via Alberto da Giussano 12, I-21052 Busto Arsizio (Vatican City State, Holy See,) (Italy)
Publication Date:
OSTI Identifier:
21143655
Resource Type:
Journal Article
Resource Relation:
Journal Name: Biochemical and Biophysical Research Communications; Journal Volume: 369; Journal Issue: 2; Other Information: DOI: 10.1016/j.bbrc.2008.02.077; PII: S0006-291X(08)00350-1; Copyright (c) 2008 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; ALBUMINS; BLOOD SERUM; HEME; HEMOGLOBIN; INOSITOL; LIGANDS; MYOGLOBIN; NITRIC OXIDE

Citation Formats

Ascenzi, Paolo, National Institute for Infectious Diseases I.R.C.C.S. 'Lazzaro Spallanzani', Via Portuense 292, I-00149 Roma, Imperi, Francesco, National Institute for Infectious Diseases I.R.C.C.S. 'Lazzaro Spallanzani', Via Portuense 292, I-00149 Roma, Coletta, Massimo, and Fasano, Mauro. Abacavir and warfarin modulate allosterically kinetics of NO dissociation from ferrous nitrosylated human serum heme-albumin. United States: N. p., 2008. Web. doi:10.1016/j.bbrc.2008.02.077.
Ascenzi, Paolo, National Institute for Infectious Diseases I.R.C.C.S. 'Lazzaro Spallanzani', Via Portuense 292, I-00149 Roma, Imperi, Francesco, National Institute for Infectious Diseases I.R.C.C.S. 'Lazzaro Spallanzani', Via Portuense 292, I-00149 Roma, Coletta, Massimo, & Fasano, Mauro. Abacavir and warfarin modulate allosterically kinetics of NO dissociation from ferrous nitrosylated human serum heme-albumin. United States. doi:10.1016/j.bbrc.2008.02.077.
Ascenzi, Paolo, National Institute for Infectious Diseases I.R.C.C.S. 'Lazzaro Spallanzani', Via Portuense 292, I-00149 Roma, Imperi, Francesco, National Institute for Infectious Diseases I.R.C.C.S. 'Lazzaro Spallanzani', Via Portuense 292, I-00149 Roma, Coletta, Massimo, and Fasano, Mauro. Fri . "Abacavir and warfarin modulate allosterically kinetics of NO dissociation from ferrous nitrosylated human serum heme-albumin". United States. doi:10.1016/j.bbrc.2008.02.077.
@article{osti_21143655,
title = {Abacavir and warfarin modulate allosterically kinetics of NO dissociation from ferrous nitrosylated human serum heme-albumin},
author = {Ascenzi, Paolo and National Institute for Infectious Diseases I.R.C.C.S. 'Lazzaro Spallanzani', Via Portuense 292, I-00149 Roma and Imperi, Francesco and National Institute for Infectious Diseases I.R.C.C.S. 'Lazzaro Spallanzani', Via Portuense 292, I-00149 Roma and Coletta, Massimo and Fasano, Mauro},
abstractNote = {Human serum albumin (HSA) participates to heme scavenging, in turn HSA-heme binds gaseous diatomic ligands at the heme-Fe-atom. Here, the effect of abacavir and warfarin on denitrosylation kinetics of HSA-heme-Fe(II)-NO (i.e., k{sub off}) is reported. In the absence of drugs, the value of k{sub off} is (1.3 {+-} 0.2) x 10{sup -4} s{sup -1}. Abacavir and warfarin facilitate NO dissociation from HSA-heme-Fe(II)-NO, the k{sub off} value increases to (8.6 {+-} 0.9) x 10{sup -4} s{sup -1}. From the dependence of k{sub off} on the drug concentration, values of the dissociation equilibrium constant for the abacavir and warfarin binding to HSA-heme-Fe(II)-NO (i.e., K = (1.2 {+-} 0.2) x 10{sup -3} M and (6.2 {+-} 0.7) x 10{sup -5} M, respectively) were determined. The increase of k{sub off} values reflects the stabilization of the basic form of HSA-heme-Fe by ligands (e.g., abacavir and warfarin) that bind to Sudlow's site I. This event parallels the stabilization of the six-coordinate derivative of the HSA-heme-Fe(II)-NO atom. Present data highlight the allosteric modulation of HSA-heme-Fe(II) reactivity by heterotropic effectors.},
doi = {10.1016/j.bbrc.2008.02.077},
journal = {Biochemical and Biophysical Research Communications},
number = 2,
volume = 369,
place = {United States},
year = {Fri May 02 00:00:00 EDT 2008},
month = {Fri May 02 00:00:00 EDT 2008}
}
  • Research highlights: {yields} Human serum heme-albumin displays globin-like properties. {yields} O{sub 2}-mediated oxidation of ferrous nitrosylated human serum heme-albumin. {yields} Allosteric modulation of human serum heme-albumin reactivity. {yields} Rifampicin is an allosteric effector of human serum heme-albumin. {yields} Human serum heme-albumin is a ROS and NOS scavenger. -- Abstract: Human serum heme-albumin (HSA-heme-Fe) displays globin-like properties. Here, kinetics of O{sub 2}-mediated oxidation of ferrous nitrosylated HSA-heme-Fe (HSA-heme-Fe(II)-NO) is reported. Values of the first-order rate constants for O{sub 2}-mediated oxidation of HSA-heme-Fe(II)-NO (i.e., for ferric HSA-heme-Fe formation) and for NO dissociation from HSA-heme-Fe(II)-NO (i.e., for NO replacement by CO) are kmore » = 9.8 x 10{sup -5} and 8.3 x 10{sup -4} s{sup -1}, and h = 1.3 x 10{sup -4} and 8.5 x 10{sup -4} s{sup -1}, in the absence and presence of rifampicin, respectively, at pH = 7.0 and T = 20.0 {sup o}C. The coincidence of values of k and h indicates that NO dissociation represents the rate limiting step of O{sub 2}-mediated oxidation of HSA-heme-Fe(II)-NO. Mixing HSA-heme-Fe(II)-NO with O{sub 2} does not lead to the formation of the transient adduct(s), but leads to the final ferric HSA-heme-Fe derivative. These results reflect the fast O{sub 2}-mediated oxidation of ferrous HSA-heme-Fe and highlight the role of drugs in modulating allosterically the heme-Fe-atom reactivity.« less
  • Ferric human serum heme-albumin (heme-HSA) shows a peculiar nuclear magnetic relaxation dispersion (NMRD) behavior that allows to investigate structural and functional properties. Here, we report a thermodynamic analysis of NMRD profiles of heme-HSA between 20 and 60 {sup o}C to characterize its hydration. NMRD profiles, all showing two Lorentzian dispersions at 0.3 and 60 MHz, were analyzed in terms of modulation of the zero field splitting tensor for the S = {sup 5}/{sub 2} manifold. Values of correlation times for tensor fluctuation ({tau}{sub v}) and chemical exchange of water molecules ({tau}{sub M}) show the expected temperature dependence, with activation enthalpiesmore » of -1.94 and -2.46 {+-} 0.2 kJ mol{sup -1}, respectively. The cluster of water molecules located in the close proximity of the heme is progressively reduced in size by increasing the temperature, with {Delta}H = 68 {+-} 28 kJ mol{sup -1} and {Delta}S = 200 {+-} 80 J mol{sup -1} K{sup -1}. These results highlight the role of the water solvent in heme-HSA structure-function relationships.« less
  • Human serum transferrin (HSTF), human serum albumin (HSA) and rat serum were compared for their interaction with AlCl[sub 3], in a Tris-HCl buffer solutions. The AlCl[sub 3] was tested in series of concentrations in the range of 50 [mu]M up to 500 [mu]M. HSTF, HSA and their 1:1 mixture and rat serum were incubated at 37 C with series of AlCl[sub 3] concentrations. The protein profile of the incubated solutions were compared to control using SDS-PAGE and FPLC tests. The results indicated that HSTF was more specifically responsive to AlCl[sub 3] showing a characteristic increase in it UV absorption, peakmore » and area dimensions. Simultaneously, HSA was less affected, but it showed a significant shift with an increase in molecular weight accompanied with a change in its profile. The respective bands of transferrin and albumin in rat serum behaved similarly.« less
  • The structural changes in four genetic variants of human serum albumin were analyzed by tandem high-pressure liquid chromatography (HPLC) of the tryptic peptides, HPLC mapping and isoelectric focusing of the CNBr fragments, and amino acid sequence analysis of the purified peptides. Lysine-372 of normal (common) albumin A was changed to glutamic acid both in albumin Naskapi, a widespread polymorphic variant of North American Indians, and in albumin Mersin found in Eti Turks. The two variants also exhibited anomalous migration in NaDodSO/sub 4//PAGE, which is attributed to a conformational change. The identity of albumins Naskapi and Mersin may have originated throughmore » descent from a common mid-Asiatic founder of the two migrating ethnic groups, or it may represent identical but independent mutations of the albumin gene. In albumin Adana, from Eti Turks, the substitution site was not identified but was localized to the region from positions 447 through 548. The substitution of aspartic acid-550 by glycine was found in albumin Mexico-2 from four individuals of the Pima tribe. Although only single-point substitutions have been found in these and in certain other genetic variants of human albumin, five differences exist in the amino acid sequences inferred from cDNA sequences by workers in three other laboratories. However, our results on albumin A and on 14 different genetic variants accord with the amino acid sequence of albumin deduced from the genomic sequence. The apparent amino acid substitutions inferred from comparison of individual cDNA sequences probably reflect artifacts in cloning or in cDNA sequence analysis rather than polymorphism of the coding sections of the albumin gene.« less