Hydrogen bond donation to the heme distal ligand of Staphylococcus aureus IsdG tunes the electronic structure
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| 024 | 7 | 0 | |a 10.1007/s00775-015-1263-5 |2 doi |
| 035 | |a (NATIONALLICENCE)springer-10.1007/s00775-015-1263-5 | ||
| 245 | 0 | 0 | |a Hydrogen bond donation to the heme distal ligand of Staphylococcus aureus IsdG tunes the electronic structure |h [Elektronische Daten] |c [Cheryl Lockhart, Matthew Conger, Dylanger Pittman, Matthew Liptak] |
| 520 | 3 | |a Staphylococcus aureus IsdG catalyzes the final step of staphylococcal iron acquisition from host hemoglobin, whereby host-derived heme is converted to iron and organic products. The Asn7 distal pocket residue is known to be critical for enzyme activity, but the influence of this residue on the substrate electronic structure was unknown prior to this work. Here, an optical spectroscopic and density functional theory characterization of azide- and cyanide-inhibited wild type and N7A IsdG is presented. Magnetic circular dichroism data demonstrate that Asn7 perturbs the electronic structure of azide-inhibited, but not cyanide-inhibited, IsdG. As the iron-ligating α-atom of azide, but not cyanide, can act as a hydrogen bond acceptor, these data indicate that the terminal amide of Asn7 is a hydrogen bond donor to the α-atom of a distal ligand to heme in IsdG. Circular dichroism characterization of azide- and cyanide-inhibited forms of WT and N7A IsdG strongly suggests that the Asn7···N3 hydrogen bond influences the orientation of a distal azide ligand with respect to the heme substrate. Specifically, density functional theory calculations suggest that Asn7···N3 hydrogen bond donation causes the azide ligand to rotate about an axis perpendicular to the porphyrin plane and weakens the π-donor strength of the azide ligand. This lowers the energies of the Fe 3d xz and 3d yz orbitals, mixes Fe 3d xy and porphyrin a 2u character into the singly-occupied molecular orbital, and results in spin delocalization onto the heme meso carbons. These discoveries have important implications for the mechanism of heme oxygenation catalyzed by IsdG. | |
| 540 | |a SBIC, 2015 | ||
| 690 | 7 | |a Circular dichroism |2 nationallicence | |
| 690 | 7 | |a Density functional theory |2 nationallicence | |
| 690 | 7 | |a Heme oxygenase |2 nationallicence | |
| 690 | 7 | |a Magnetic circular dichroism |2 nationallicence | |
| 690 | 7 | |a Second-sphere interactions |2 nationallicence | |
| 690 | 7 | |a Abs : Electronic absorption |2 nationallicence | |
| 690 | 7 | |a CD : Circular dichroism |2 nationallicence | |
| 690 | 7 | |a DFT : Density functional theory |2 nationallicence | |
| 690 | 7 | |a Fe(III)TMP(4-CNPy)2 : Bis(4-cyanopyridine)ferrictetramesitylporphyrinate |2 nationallicence | |
| 690 | 7 | |a Isd : Iron-regulated surface determinant |2 nationallicence | |
| 690 | 7 | |a IsdG-heme : Heme-bound IsdG |2 nationallicence | |
| 690 | 7 | |a IsdG-heme-CN : Cyanide-inhibited IsdG |2 nationallicence | |
| 690 | 7 | |a IsdG-heme-N3 : Azide-inhibited IsdG |2 nationallicence | |
| 690 | 7 | |a IsdG-heme-OOH : Hydroperoxo-ligated, heme-bound IsdG |2 nationallicence | |
| 690 | 7 | |a IsdI-heme-OH : Hydroxide-ligated, heme-bound IsdI |2 nationallicence | |
| 690 | 7 | |a KPi : Potassium phosphate |2 nationallicence | |
| 690 | 7 | |a MCD : Magnetic circular dichroism |2 nationallicence | |
| 690 | 7 | |a NaPi : Sodium phosphate |2 nationallicence | |
| 690 | 7 | |a PMSF : Phenylmethanesulfonyl fluoride |2 nationallicence | |
| 690 | 7 | |a TEV : Tobacco etch virus |2 nationallicence | |
| 690 | 7 | |a VTVH : Variable-temperature, variable-field |2 nationallicence | |
| 690 | 7 | |a WT : Wild-type |2 nationallicence | |
| 700 | 1 | |a Lockhart |D Cheryl |u Department of Chemistry, University of Vermont, 82 University Place, 05405, Burlington, VT, USA |4 aut | |
| 700 | 1 | |a Conger |D Matthew |u Department of Chemistry, University of Vermont, 82 University Place, 05405, Burlington, VT, USA |4 aut | |
| 700 | 1 | |a Pittman |D Dylanger |u Department of Chemistry, University of Vermont, 82 University Place, 05405, Burlington, VT, USA |4 aut | |
| 700 | 1 | |a Liptak |D Matthew |u Department of Chemistry, University of Vermont, 82 University Place, 05405, Burlington, VT, USA |4 aut | |
| 773 | 0 | |t JBIC Journal of Biological Inorganic Chemistry |d Springer Berlin Heidelberg |g 20/5(2015-07-01), 757-770 |x 0949-8257 |q 20:5<757 |1 2015 |2 20 |o 775 | |
| 856 | 4 | 0 | |u https://doi.org/10.1007/s00775-015-1263-5 |q text/html |z Onlinezugriff via DOI |
| 898 | |a BK010053 |b XK010053 |c XK010000 | ||
| 900 | 7 | |a Metadata rights reserved |b Springer special CC-BY-NC licence |2 nationallicence | |
| 908 | |D 1 |a research-article |2 jats | ||
| 949 | |B NATIONALLICENCE |F NATIONALLICENCE |b NL-springer | ||
| 950 | |B NATIONALLICENCE |P 856 |E 40 |u https://doi.org/10.1007/s00775-015-1263-5 |q text/html |z Onlinezugriff via DOI | ||
| 950 | |B NATIONALLICENCE |P 700 |E 1- |a Lockhart |D Cheryl |u Department of Chemistry, University of Vermont, 82 University Place, 05405, Burlington, VT, USA |4 aut | ||
| 950 | |B NATIONALLICENCE |P 700 |E 1- |a Conger |D Matthew |u Department of Chemistry, University of Vermont, 82 University Place, 05405, Burlington, VT, USA |4 aut | ||
| 950 | |B NATIONALLICENCE |P 700 |E 1- |a Pittman |D Dylanger |u Department of Chemistry, University of Vermont, 82 University Place, 05405, Burlington, VT, USA |4 aut | ||
| 950 | |B NATIONALLICENCE |P 700 |E 1- |a Liptak |D Matthew |u Department of Chemistry, University of Vermont, 82 University Place, 05405, Burlington, VT, USA |4 aut | ||
| 950 | |B NATIONALLICENCE |P 773 |E 0- |t JBIC Journal of Biological Inorganic Chemistry |d Springer Berlin Heidelberg |g 20/5(2015-07-01), 757-770 |x 0949-8257 |q 20:5<757 |1 2015 |2 20 |o 775 | ||