Carbon Monoxide Recombination Dynamics in Truncated Hemoglobins Studied with Visible-Pump MidIR-Probe Spectroscopy
Lapini Andrea, Di Donato Mariangela, Patrizi Barbara, Marcelli Agnese, Lima Manuela, Righini Roberto, Foggi Paolo [, ], Sciamanna Natascia, Boffi Alberto
Materials Chemistry Coatings and Films MESH: Truncated Hemoglobins Infrared Molecular Biology Bacillus subtilis Carbon Monoxide Surfaces INFRARED-SPECTROSCOPY Truncated Hemoglobins PRIMARY DOCKING SITE Actinomycetales OXYGEN SENSOR FIXL MESH: Photolysis Photolysis Light Heme MESH: Actinomycetales MESH: Heme MESH: Bacillus subtilis HEME POCKET [SDV.BBM]Life Sciences [q-bio]/Biochemistry MESH: Kinetics MESH: Spectrophotometry BACILLUS-SUBTILIS Kinetics Spectrophotometry MESH: Light MESH: Carbon Monoxide Physical and Theoretical Chemistry
Carbon monoxide recombination dynamics upon photodissociation with visible light has been characterized by means of ultrafast visible-pump/MidIR probe spectroscopy for the truncated hemoglobins from Thermobifida fusca and Bacillus subtilis. Photodissociation has been induced by exciting the sample at two different wavelengths: 400 nm, corresponding to the heme absorption in the B-band, and 550 nm, in the Q-bands. The bleached iron-CO coordination band located at 1850-1950 cm(-1) and the free CO absorption band in the region 2050-2200 cm(-1) have been observed by probe pulses tuned in the appropriate infrared region. The kinetic traces measured at 1850-1950 cm(-1) reveal naultiexponential subnanosecond dynamics that have been interpreted as arising from fast geminate recombination of the photolyzed CO. A compared analysis of the crystal structure of the two proteins reveals a similar structure of their distal heme pocket, which contains conserved polar and aromatic amino acid residues closely interacting with the iron ligand. Although fast geminate recombination is observed in both proteins, several kinetic differences can be evidenced, which can be interpreted in terms of a different structural flexibility of the corresponding heme distal pockets. The analysis of the free CO band-shape and of its dynamic evolution brings out novel features about the nature of the docking site inside the protein cavity.
Source: The journal of physical chemistry. B 116 (2012): 8753–8761. doi:10.1021/jp3019149
Publisher: American Chemical Society,, Washington, D.C. , Stati Uniti d'America
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@article{oai:it.cnr:prodotti:206069,
title = {Carbon Monoxide Recombination Dynamics in Truncated Hemoglobins Studied with Visible-Pump MidIR-Probe Spectroscopy},
author = {Lapini Andrea and Di Donato Mariangela and Patrizi Barbara and Marcelli Agnese and Lima Manuela and Righini Roberto and Foggi Paolo [ and ] and Sciamanna Natascia and Boffi Alberto},
publisher = {American Chemical Society,, Washington, D.C. , Stati Uniti d'America},
doi = {10.1021/jp3019149},
journal = {The journal of physical chemistry. B},
volume = {116},
pages = {8753–8761},
year = {2012}
}
