The heme pocket of the globin domain of the globin-coupled sensor of Geobacter sulfurreducens — An EPR study

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• 作者：Filip Desmet ; Liesbet Thijs ; Hassane El Mkami ; Sylvia Dewilde ; Luc Moens ; Graham Smith ; Sabine Van Doorslaer
• 关键词：Globin-coupled sensors ; Electron paramagnetic resonance ; Ligand orientation
• 刊名：Journal of Inorganic Biochemistry
• 出版年：2010
• 出版时间：October 2010
• 年：2010
• 卷：104
• 期：10
• 页码：1022-1028
• 全文大小：532 K

文摘

The globin-coupled sensor (GCS) of Geobacter sulfurreducens is unique amongst GCSs in that its signalling domain is a transmembrane domain with yet unknown function. In the present work we use X-band continuous-wave and pulsed electron paramagnetic resonance (EPR) to investigate the ferric form of the globin domain of the G. sulfurreducens GCS (GsGCS¹⁶²) at pH 8.5. This form shows a unique bis-histidine coordination of the heme with the F8His and E11His. In contrast with previous crystal structure data, where three conformers of the heme structure were identified, ferric GsGCS¹⁶² assumes only one conformation in frozen solution. The EPR data of ferric GsGCS162 are compared in detail with those of other bis-histidine coordinated globins, including other GCS systems.