NRVS study of diatomic gas sensing mechanism of hemoproteins

2019 Fiscal Year Final Research Report

• Project/Area Number: 16K05850
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Bio-related chemistry
• Research Institution: Tokyo University of Science, Yamaguchi (2018-2019); University of Hyogo (2016-2017)
• Principal Investigator: OHTA Takehiro 山陽小野田市立山口東京理科大学, 工学部, 准教授 (70509950)
• Project Period (FY): 2016-04-01 – 2020-03-31
• Keywords: 核共鳴非弾性散乱分光 / 共鳴ラマン分光 / ヘム蛋白質 / 気体センサー蛋白質

Outline of Final Research Achievements

Nuclear resonance vibrational spectroscopy (NRVS) was applied to myoglobin. The nature of Fe－O2 bond in oxy Hb and Mb had been extensively investigated by resonance Raman spectroscopy, which assigned the Fe－O2 stretching bands at 570 cm－1. However, resonance Raman assignment of the vibrational mode had been elusive due to the spectroscopic selection rule and to the limited information available about the ground-state molecular structure. NRVS analyses in conjunction with DFT calculations gave new insights into the nature of the Fe－O2 bond of oxy heme by revealing the effect of heme peripheral substitutions on the vibrational dynamics of heme Fe atom, where the main Fe－O2 stretching band of the native protein was characterized at 420 cm－1. Thus, NRVS shed new light on the molecular mechanism of hemproteins that function upon binding of diatomic gas molecules.

Free Research Field

生物無機化学 錯体化学 振動分光学

Academic Significance and Societal Importance of the Research Achievements

気体分子結合型ヘムの分子構造の解析は、各種ヘム蛋白質の分子機構の解明に重要である。本研究では、放射光施設を利用した核共鳴非弾性散乱分光法 (NRVS) により、ミオグロビンのヘム鉄近傍の分子振動構造解析を行った。酸素結合型ミオグロビンの解析では、ヘム鉄－酸素結合の分子振動構造について、従来の見解とは異なる新たな知見を得た。本成果は、酸素もしくは他の2原子気体分子と相互作用し、分子内情報伝達により機能発現する各種ヘム蛋白質の研究に新たな展開をもたらす。