caa a22 4500 605507279 CHVBK 20210128100631.0 cr unu---uuuuu 210128e20150401xx s 000 0 eng 10.1007/s00775-014-1236-0 doi (NATIONALLICENCE)springer-10.1007/s00775-014-1236-0 Carbon monoxide binding properties of domain-swapped dimeric myoglobin [Elektronische Daten] [Satoshi Nagao, Haruto Ishikawa, Takuya Yamada, Yasuhisa Mizutani, Shun Hirota] Myoglobin (Mb) is a monomeric oxygen storage hemoprotein, and has been shown to form a domain-swapped dimer. In this study, monomeric and dimeric carbon monoxide (CO)-bound Mb (MbCO) exhibited similar absorption spectra. The CO stretching frequencies of MbCO were observed at 1,932 and 1,944cm−1 for both monomeric and dimeric MbCO. The resonance Raman (RR) bands for the stretching between the heme iron and axial ligands were observed at the same frequencies for the monomer and dimer of deoxygenated Mb (deoxyMb) and MbCO, respectively (ν Fe-His, 220cm−1; ν Fe-C, 507cm−1), showing that the Fe-His bond strength of deoxyMb and the Fe-CO bond strength of MbCO did not change by the dimerization. Time-resolved RR measurements showed that the dynamics of the structural changes at the heme active site after CO photo-dissociation of MbCO was similar between monomeric and dimeric Mb [monomer, (5.2±1.8)×106s−1; dimer, (6.2±1.1)×106s−1 at room temperature]. These results show that the heme coordination structure, the protein environment around the bound CO, and the protein relaxation character are similar between monomeric and dimeric MbCO. Although the active site structure was similar between the monomer and dimer, the CO binding rate constant of dimeric Mb [(1.01±0.03)×106M−1s−1 at 20°C] was about twice larger than that of the monomer [(0.52±0.02)×106M−1s−1 at 20°C], presumably due to the expansion of the channel between the Xe3 cavity and the solvent by the dimerization. SBIC, 2015 Myoglobin nationallicence Domain swapping nationallicence Ligand binding nationallicence Active site structure nationallicence Nagao Satoshi Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5, Takayama, 630-0192, Ikoma, Nara, Japan aut Ishikawa Haruto Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, 560-0043, Toyonaka, Japan aut Yamada Takuya Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5, Takayama, 630-0192, Ikoma, Nara, Japan aut Mizutani Yasuhisa Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, 560-0043, Toyonaka, Japan aut Hirota Shun Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5, Takayama, 630-0192, Ikoma, Nara, Japan aut JBIC Journal of Biological Inorganic Chemistry Springer Berlin Heidelberg 20/3(2015-04-01), 523-530 0949-8257 20:3<523 2015 20 775 https://doi.org/10.1007/s00775-014-1236-0 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00775-014-1236-0 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Nagao Satoshi Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5, Takayama, 630-0192, Ikoma, Nara, Japan aut NATIONALLICENCE 700 1- Ishikawa Haruto Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, 560-0043, Toyonaka, Japan aut NATIONALLICENCE 700 1- Yamada Takuya Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5, Takayama, 630-0192, Ikoma, Nara, Japan aut NATIONALLICENCE 700 1- Mizutani Yasuhisa Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, 560-0043, Toyonaka, Japan aut NATIONALLICENCE 700 1- Hirota Shun Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5, Takayama, 630-0192, Ikoma, Nara, Japan aut NATIONALLICENCE 773 0- JBIC Journal of Biological Inorganic Chemistry Springer Berlin Heidelberg 20/3(2015-04-01), 523-530 0949-8257 20:3<523 2015 20 775