caa a22 4500 475744241 CHVBK 20180406123508.0 cr unu---uuuuu 170329e20000401xx s 000 0 eng 10.1023/A:1007016105813 doi (NATIONALLICENCE)springer-10.1023/A:1007016105813 Heme Binding by Hemopexin: Evidence for Multiple Modes of Binding and Functional Implications [Elektronische Daten] [Natalia Shipulina, Ann Smith, William Morgan] Hemopexin binds 1 mol of heme per mol with high affinity (K d < 1 pM) in a low-spin complex and acts as a transport vehicle for the heme. Circular dichroism (CD) spectroscopy was used to examine the heme environment in the ferri-, ferro-, and CO-ferro complexes of four iron tetrapyrroles [meso-, proto-, deutero-, and (2-vinyl, 4-hydroxymethyl)-deutero-heme] with three species (human, rabbit, and rat) of hemopexin. All ferri-heme-hemopexin complexes exhibit a band of positive ellipticity near the Soret maximum, except for the human ferri-protoheme hemopexin complex, which has a bisignate spectrum. The ferro-heme and CO-ferro-heme complexes display a variety of spectra, demonstrating redox- and ligand-linked shifts in conformation that alter the environment of the heme. The rabbit mesoheme-N-domain complexes have absorbance spectra almost indistinguishable from those of intact hemopexin, but present CD spectra that are distinctly different. However, adding the C-domain to mesoheme-N-domain restores most of the CD characteristics of the intact hemopexin complexes. Plenum Publishing Corporation, 2000 Hemopexin nationallicence heme nationallicence circular dichroism nationallicence spectroscopy nationallicence CO-binding nationallicence Shipulina Natalia Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri-Kansas City, 64110, Kansas City, Missouri aut Smith Ann Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri-Kansas City, 64110, Kansas City, Missouri aut Morgan William Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri-Kansas City, 64110, Kansas City, Missouri aut Journal of Protein Chemistry Kluwer Academic Publishers-Plenum Publishers 19/3(2000-04-01), 239-248 0277-8033 19:3<239 2000 19 10930 https://doi.org/10.1023/A:1007016105813 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1023/A:1007016105813 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Shipulina Natalia Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri-Kansas City, 64110, Kansas City, Missouri aut NATIONALLICENCE 700 1- Smith Ann Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri-Kansas City, 64110, Kansas City, Missouri aut NATIONALLICENCE 700 1- Morgan William Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri-Kansas City, 64110, Kansas City, Missouri aut NATIONALLICENCE 773 0- Journal of Protein Chemistry Kluwer Academic Publishers-Plenum Publishers 19/3(2000-04-01), 239-248 0277-8033 19:3<239 2000 19 10930 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer