ESEEM Reveals Bound Substrate Histidine in the ABC Transporter HisQMP(2)
Autor(en): | Isaev, Nikolay Heuveling, Johanna Ivanisenko, Nikita Schneider, Erwin Steinhoff, Heinz-Juergen |
Stichwörter: | BINDING; DIVERSITY; ELECTRON-SPIN-ECHO; ENVELOPE MODULATION; EPR SPECTROSCOPY; INVESTIGATE; MEMBRANE; Physics; Physics, Atomic, Molecular & Chemical; PROTEINS; RADICALS; Spectroscopy; WATER CONCENTRATION | Erscheinungsdatum: | 2019 | Herausgeber: | SPRINGER WIEN | Journal: | APPLIED MAGNETIC RESONANCE | Volumen: | 50 | Ausgabe: | 7 | Startseite: | 883 | Seitenende: | 893 | Zusammenfassung: | Localization of substrates in membrane proteins is an important but challenging task. In this paper, we show that deuterium electron spin echo envelopemodulation spectroscopy ((HESEEM)-H-2) combined with site-directed spin labeling is a powerful tool to localize the substrate, histidine-d5, in the ABC transporter HisQMP(2). Based on a homology model and spin label rotamer analyses, we calculated (HESEEM)-H-2 spectra for eight possible labeling positions close to the putative substrate-binding site. Experimental (HESEEM)-H-2 spectra were determined with spin labels bound either at position 169 of HisM, for which a detectable (HESEEM)-H-2 signal was calculated, or with a spin label bound at position 54 of HisQ as a negative control. The agreement between the calculated and experimental ESEEM spectra provides strong evidence for the histidine located in a binding site primarily liganded by residues of HisM as proposed by the homology model. |
ISSN: | 09379347 | DOI: | 10.1007/s00723-019-01114-y |
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