Correlation between the iron-histidine stretching frequencies and oxygen affinity of hemoglobins. A continuous strain model

Matsukawa, Shigeru; Mawatari, Kazuhiro; Yoneyama, Yoshimasa; Kitagawa, Teizo

doi:10.1021/ja00291a004

Cited by 78 publications

(82 citation statements)

References 3 publications

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“…Thus, the affinity of Fe a3 for CO is expected to be controlled by the coordination structure of the fifth ligand of heme a 3 , His-376, in the relay system. A subtle structural change in the coordination structure of the heme iron could greatly influence the ligand affinity as in the case of O 2 affinity of hemoglobin (56,57).…”

Section: Discussionmentioning

confidence: 99%

Effective Pumping Proton Collection Facilitated by a Copper Site (CuB) of Bovine Heart Cytochrome c Oxidase, Revealed by a Newly Developed Time-resolved Infrared System

Kubo¹,

Nakashima²,

Yamaguchi

et al. 2013

Journal of Biological Chemistry

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Background: Cytochrome c oxidase reduces O 2 coupled with proton pumping. Results: A newly developed time-resolved infrared system reveals transient conformational changes in the proton-pumping pathway upon CO binding to Cu B in the O 2 reduction site. Conclusion: Cu B promotes proton collection and effective blockage of back-leak of pumping protons. Significance: These critical findings in bioenergetics stimulate the new infrared approach for mechanistic investigation of any other protein function.

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Section: Discussionmentioning

confidence: 99%

Effective Pumping Proton Collection Facilitated by a Copper Site (CuB) of Bovine Heart Cytochrome c Oxidase, Revealed by a Newly Developed Time-resolved Infrared System

Kubo¹,

Nakashima²,

Yamaguchi

et al. 2013

Journal of Biological Chemistry

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“…The low Fe-His frequency is a consequence of the strain in the T quaternary structure, and the magnitude of strain is directly related to oxygen affinity (68). In the absence of strain, the Fe-His frequency is close to that of deoxy Mb.…”

Section: Resonance Raman and Ligand Binding Studies Of Hemat-bsmentioning

confidence: 90%

Resonance Raman and Ligand Binding Studies of the Oxygen-sensing Signal Transducer Protein HemAT from Bacillus subtilis

Aono¹,

Kato²,

Matsuki³

et al. 2002

Journal of Biological Chemistry

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HemAT-Bs is a heme-containing signal transducer protein responsible for aerotaxis of Bacillus subtilis. The recombinant HemAT-Bs expressed in Escherichia coli was purified as the oxy form in which oxygen was bound to the ferrous heme. Oxygen binding and dissociation rate constants were determined to be k on ‫؍‬ 32 M ؊1 s ؊1 and k off ‫؍‬ 23 s ؊1 , respectively, revealing that HemAT-Bs has a moderate oxygen affinity similar to that of sperm whale myoglobin (Mb). The rate constant for autoxidation at 37°C was 0.06 h ؊1 , which is also close to that of Mb. Although the electronic absorption spectra of HemAT-Bs were similar to those of Mb, HemAT-Bs showed some unique characteristics in its resonance Raman spectra. Oxygen-bound HemAT-Bs gave the Fe-O 2 band at a noticeably low frequency (560 cm ؊1 ), which suggests a unique hydrogen bonding between a distal amino acid residue and the proximal atom of the bound oxygen molecule. Deoxy HemAT-Bs gave the Fe-His band at a higher frequency (225 cm ؊1 ) than those of ordinary His-coordinated deoxy heme proteins. CObound HemAT-Bs gave the Fe-CO and C-O bands at 494 and 1964 cm ؊1 , respectively, which fall on the same C-O versus Fe-CO correlation line as that of Mb. Based on these results, the structural and functional properties of HemAT-Bs are discussed.Motile bacteria are known to swim toward or away from specific environmental stimuli such as nutrients, oxygen, or light (1, 2). This behavior, termed chemotaxis, is mediated by a signal transduction system consisting of methyl-accepting chemotaxis proteins (MCPs), 1 a histidine kinase CheA, a response regulator CheY, a coupling protein CheW, and the two enzymes that mediate sensory adaptation by covalently modifying the MCPs, CheR and CheB (3-6). Typical MCP is an integral membrane protein with an N-terminal periplasmic substrate binding domain and a C-terminal cytoplasmic signaling domain (7,8). The binding of a substrate, a repellent, or attractant to the periplasmic substrate binding domain is believed to induce a change in the MCP conformation that allows it to activate CheA (7, 8). The activated CheA phosphorylates CheY, and, consequently, the phosphorylated CheY binds to the switch complex at the base of the flagella to control the direction of flagellar rotation (3-6). In this signal transduction system, MCP acts as a sensor for the external signal and as a signal transducer.Hou et al. (9) have recently reported that Bacillus subtilis and Halobacterium salinarum have a signal transducer protein, HemAT-Bs and HemAT-Hs, respectively, for aerotaxis, the migratory response toward or away from oxygen. HemAT-Bs and HemAT-Hs are soluble proteins, and their C-terminal regions, residues 222-489 of HemAT-Hs and 198 -432 of HemAT-Bs, are 30% identical to the cytoplasmic signaling domain of Tsr, an MCP from Escherichia coli (9). Their N-terminal regions, residues 1-184 in HemAT-Hs and 1-175 in HemAT-Bs, show limited homology to myoglobin (9). Recombinant HemAT-Bs and HemAT-Hs are hemoproteins containing a b-type heme as a prost...

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“…In Hb*CO, there is good evidence that strain introduced by changes in protein conformation is communicated to the heme iron [33]. The shift of the m(Fe-His) band from 230 cm )1 in Hb*CO to 213 cm )1 in deoxy Hb provides key evidence for a mechanism that involves the communication of strain introduced at protein subunits to the diatomic binding site at the iron [33,38,39]. This 17 cm )1 shift is comparable to the shift observed in the photoproduct H93G(2-MeIm) adduct in buffer solution.…”

Section: Spectral Changes Reflect Strain and Coupling Of Ligand And Pmentioning

confidence: 99%

Proximal ligand motions in H93G myoglobin

Franzen

Peterson

Brown

et al. 2002

European Journal of Biochemistry

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Resonance Raman spectroscopy has been used to observe changes in the iron-ligand stretching frequency in photoproduct spectra of the proximal cavity mutant of myoglobin H93G. The measurements compare the deoxy ferrous state of the heme iron in H93G(L), where L is an exogenous imidazole ligand bound in the proximal cavity, to the photolyzed intermediate of H93G(L)*CO at 8 ns. There are significant differences in the frequencies of the iron-ligand axial out-of-plane mode m(Fe-L) in the photoproduct spectra depending on the nature of L for a series of methylsubstituted imidazoles. Further comparison was made with the proximal cavity mutant of myoglobin in the absence of exogenous ligand (H93G) and the photoproduct of the carbonmonoxy adduct of H93G (H93G-*CO). For this case, it has been shown that H 2 O is the axial (fifth) ligand to the heme iron in the deoxy form of H93G. The photoproduct of H93G-*CO is consistent with a transiently bound ligand proposed to be a histidine. The data presented here further substantiate the conclusion that a conformationally driven ligand switch exists in photolyzed H93G-*CO. The results suggest that ligand conformational changes in response to dynamic motions of the globin on the nanosecond and longer time scales are a general feature of the H93G proximal cavity mutant.Keywords: resonance Raman, heme, myoglobin, hemoglobin, ligand switch.Protein structural relaxation following heme photolysis has been studied in globins as a means to obtain information on structural intermediates following diatomic ligand photolysis. In hemoglobin (Hb), time-resolved spectroscopic studies have provided information on the time scale for transition from the six-coordinate R state to the fivecoordinate T-state [1][2][3]. The proximal cavity mutant of Hb has recently demonstrated the key role of the proximal histidine in the cooperativity of quaternary structure change in response to ligand binding [4]. Strain in the covalent bond to the heme iron of Hb can be monitored by following the shift in frequency of the iron-histidine axial mode, m(FeHis), by time-resolved resonance Raman spectroscopy [5]. In myoglobin (Mb), these studies have indicated a much smaller change in structure [6]: the observed frequency shift of the iron-histidine band is c. 1.6 cm )1 on the 8 ns time scale compared to 12 cm )1 in Hb. Nonetheless, this shift in the m(Fe-His) Raman band is significant because shifts in absorption bands (the time-dependent Soret band shift and band III shift) have been attributed to iron out-of-plane displacement that should also be coupled to m(Fe-His) [7][8][9][10]. A structural interpretation of these observable phenomena helps to bridge the gap between the extensive X-ray crystallography studies and the thermodynamic and kinetic data available for Mb [7,[11][12][13][14][15][16][17][18][19][20].Histidine-ligated heme enzymes have a surprisingly large range of functions. In peroxidase, a charge relay due to hydrogen bonding of the imidazole ring of histidine permits the formation of high valent iro...

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Correlation between the iron-histidine stretching frequencies and oxygen affinity of hemoglobins. A continuous strain model

Cited by 78 publications

References 3 publications

Effective Pumping Proton Collection Facilitated by a Copper Site (CuB) of Bovine Heart Cytochrome c Oxidase, Revealed by a Newly Developed Time-resolved Infrared System

Effective Pumping Proton Collection Facilitated by a Copper Site (CuB) of Bovine Heart Cytochrome c Oxidase, Revealed by a Newly Developed Time-resolved Infrared System

Resonance Raman and Ligand Binding Studies of the Oxygen-sensing Signal Transducer Protein HemAT from Bacillus subtilis

Proximal ligand motions in H93G myoglobin

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