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| Type |
Poster Presentation |
| Area |
Physical Chemistry |
| Room No. |
Grand Ballroom |
| Time |
10월 19일 (금요일) 11:00~12:30 |
| Code |
PHYS.P-206 |
| Subject |
Rebinding Dynamics of CO with Cytoglobin in Aqueous Solution Using Time-Resolved Vibratonal Spectroscopy |
| Authors |
JuHyang Shin, Manho Lim*, CheongHa Lim1
Department of Chemistry, Pusan National University, Korea
1Pusan National University, Korea
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| Abstract |
Time-resolved vibrational spectroscopy was used to investigate the rebinding dynamics of CO to cytoglobin (Cgb) in the time range of femtosecond to microsecond after photodeligation of CgbCO in D2O solution at 283 K. the stretching mode of the CO bound in CgbCO consists of three conformational bands (denoted to A0, A1, and A3). The three bands show the same immediate bleach but their decay was different: the A0 band (40% of the total initial bleach) reveals 3 ns decay but the A1 and A3 bands decay with a time constant of 260 ns, indicating that photodeligation of CgbCO proceeds on the femtosecond timescale and the geminate rebinding (GR) of CO to Cgb is dependent on the conformation of CgbCO. The stretching mode of CO photodeligated from CgbCO shows two bands in femtosecond to nanosecond timescales and becomes one bands with the pump-probe delay. The evolution of the photodeligated CO band was well described by CO band in the heme pockets, protein cavities, and in solution. When the kinetics of the photodeligated bands was modelled by combining with the kinetics of the conformational bound bands, the GR rate as well as the rate from the cavity to the heme pocket were dependent on the protein conformation. GR of two bands (A1 and A3) is similar to GR in myoglobin (Mb) but overall GR is much more efficient in Cgb due to the large contribution from A0 conformation, indicating that Cgb also has the primary docking site-like structure found in Mb that suppresses GR by restraining ligand motion but the suppression appears to be not as efficient as Mb. Relatively fast GR of the A0 conformation suggests that the binding of CO to the heme protein is very sensitive to the conformation of the protein. |
| E-mail |
dksvmflzk@gmail.com |
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122nd General Meeting of the KCS