Absorption in the Q-band region by isolated ferric heme(+) and heme(+)(histidine) in vacuo

作者：Wyer Jean Ann^*; Nielsen Steen Brondsted

来源：Journal of Chemical Physics, 2010, 133(8): 084306.

DOI：10.1063/1.3474998

Absorption by heme proteins is determined by the heme microenvironment that is often vacuumlike (hydrophobic pocket). Here we provide absorption spectra in the Q-band region of isolated ferric heme(+) and heme(+) (histidine) ions in vacuo to be used as references in protein biospectroscopy. Ions were photoexcited in an electrostatic storage ring and their decay monitored in time. Both ions display a triple band structure with maxima at 500, 518, and 530 nm. Previous attempts to study four-coordinate Fe(III)-heme(+) were hampered by the strong affinity of Fe3+ for water and anions. Absorption at higher wavelengths is also measured, which is ascribed to charge-transfer transitions from the porphyrin to the iron. Finally, our data serve to benchmark theoretical calculations.

• 出版日期2010-8-28