The D-Helix in Myoglobin and in the .beta. Subunit of Hemoglobin Is Required for the Retention of Heme

Whitaker, Timothy; Berry, Michael B.; Ho, Emai L.; Hargrove, Mark S.; Phillips, George N.; Komiyama, Noboru H.; Nagai, Kiyoshi; Olson, John S.

doi:10.1021/bi00026a002

Cited by 37 publications

(15 citation statements)

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“…Noncovalent heme-binding proteins such as myoglobin (Mb) and hemoglobin (Hb) have been extensively studied in solution [30][31][32][33][34][35][36][37][38][39][40][41][42] as well as in the gas phase [3][4][5][6][7][8]10,11,43]. In solution, the binding of ligands such as O 2 and CO [30,38,39], and the affinity of the protein for the heme group, have been studied [30][31][32][33][34][35][40][41][42] In gas-phase studies, McLuckey and Ramsey [7] reported that holo-Mb ions could be trapped for 1 s in a quadrupole ion trap mass spectrometer.…”

Section: Introductionmentioning

confidence: 99%

“…In solution, the binding of ligands such as O 2 and CO [30,38,39], and the affinity of the protein for the heme group, have been studied [30][31][32][33][34][35][40][41][42] In gas-phase studies, McLuckey and Ramsey [7] reported that holo-Mb ions could be trapped for 1 s in a quadrupole ion trap mass spectrometer. Dissociation of the 9 + charge state resulted in the production of singly charged heme and the 8 + charge state of the protein [7].…”

Section: Introductionmentioning

confidence: 99%

“…Recent studies, which probe the gas-phase conformation of ions by using H/D exchange [23,24], collisional cross section [5,25] and ion mobility [26,27], proton transfer reactivity [28,29], and high-energy surface-impact collisions [6], show that many proteins can have a highly compact conformation in the gas phase, although the exact nature of these conformations is not known. These results suggest the possibility that ions can retain some conformational attributes of their solution structure.Noncovalent heme-binding proteins such as myoglobin (Mb) and hemoglobin (Hb) have been extensively studied in solution [30][31][32][33][34][35][36][37][38][39][40][41][42] as well as in the gas phase [3][4][5][6][7][8]10,11,43]. In solution, the binding of ligands such as O 2 and CO [30,38,39], and the affinity of the protein for the heme group, have been studied [30][31][32][33][34][35][40][41][42] In gas-phase studies, McLuckey and Ramsey …”

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confidence: 99%

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Dissociation of heme-globin complexes by blackbody infrared radiative dissociation: Molecular specificity in the gas phase?

Gross

Zhao

Williams

1997

J. Am. Soc. Mass Spectrom.

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The temperature dependence of the unimolecular kinetics for dissociation of the heme group from holo-myoglobin (Mb) and holo-hemoglobin α-chain (Hb-α) was investigated with blackbody infrared radiative dissociation (BIRD). The rate constant for dissociation of the 9 + charge state of Mb formed by electrospray ionization from a "pseudo-native" solution is 60% lower than that of Hb-α at each of the temperatures investigated. In solutions of pH 5.5-8.0, the thermal dissociation rate for Mb is also lower than that of HB-α (Hargrove, M. S. et al. J. Biol. Chem. 1994, 269, 4207-4214). Thus, Mb is thermally more stable with respect to heme loss than Hb-α both in the gas phase and in solution. The Arrhenius activation parameters for both dissociation processes are indistinguishable within the current experimental error (activation energy 0.9 eV and pre-exponential factor of 10 8-10 s −1 ). The 9+ to 12+ charge states of Mb have similar Arrhenius parameters when these ions are formed from pseudo-native solutions. In contrast, the activation energies and pre-exponential factors decrease from 0.8 to 0.3 eV and 10 7 to 10 2 s −1 , respectively, for the 9 + to 12 + charge states formed from acidified solutions in which at least 50% of the secondary structure is lost. These results demonstrate that gas-phase Mb ions retain clear memory of the composition of the solution from which they are formed and that these differences can be probed by BIRD.Noncovalent interactions play a critical role in the function of biomolecules in solution [1]. Under gentle conditions, both electrospray ionization [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] and matrix-assisted laser desorption [17][18][19][20] can produce intact gas-phase ions of a variety of noncovalent biomolecule complexes. Recent studies indicate that information about the relative binding affinities of noncovalent complexes in solution can be obtained from the relative abundances of the corresponding ions observed in a mass spectrum [12][13][14][15]21]. Careful control experiments are critical [22], because other factors, such as ion source conditions and gas-phase chemistry, can influence these abundances. An important question is what structural changes occur when noncovalent complexes enter the gas phase, that is, are specific interactions retained in the absence of solvent, and if so, do their bindings strengths reflect those in solution? Recent studies, which probe the gas-phase conformation of ions by using H/D exchange [23,24], collisional cross section [5,25] and ion mobility [26,27], proton transfer reactivity [28,29], and high-energy surface-impact collisions [6], show that many proteins can have a highly compact conformation in the gas phase, although the exact nature of these conformations is not known. These results suggest the possibility that ions can retain some conformational attributes of their solution structure.Noncovalent heme-binding proteins such as myoglobin (Mb) and hemoglobin (Hb) have been extensively studied in solution [30][31][32][...

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Dissociation of heme-globin complexes by blackbody infrared radiative dissociation: Molecular specificity in the gas phase?

Gross

Zhao

Williams

1997

J. Am. Soc. Mass Spectrom.

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“…Each hemoglobin molecule contains 2 alpha chains and 2 beta chains, subunits which are identifiable by structural characteristics [13]. Alpha hemoglobins lack a specific alpha-helix, the D helix, that is present in beta hemoglobins [14]. Many organisms have several distinct hemoglobins, an adult form and embryonic or fetal forms created by combining different alpha and beta hemoglobin units [13].…”

Section: Resultsmentioning

confidence: 99%

A Rapid Method for Characterization of Protein Relatedness Using Feature Vectors

et al. 2010

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We propose a feature vector approach to characterize the variation in large data sets of biological sequences. Each candidate sequence produces a single feature vector constructed with the number and location of amino acids or nucleic acids in the sequence. The feature vector characterizes the distance between the actual sequence and a model of a theoretical sequence based on the binomial and uniform distributions. This method is distinctive in that it does not rely on sequence alignment for determining protein relatedness, allowing the user to visualize the relationships within a set of proteins without making a priori assumptions about those proteins. We apply our method to two large families of proteins: protein kinase C, and globins, including hemoglobins and myoglobins. We interpret the high-dimensional feature vectors using principal components analysis and agglomerative hierarchical clustering. We find that the feature vector retains much of the information about the original sequence. By using principal component analysis to extract information from collections of feature vectors, we are able to quickly identify the nature of variation in a collection of proteins. Where collections are phylogenetically or functionally related, this is easily detected. Hierarchical agglomerative clustering provides a means of constructing cladograms from the feature vector output.

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“…One b-turn is around a50 and a51, and the other is around a71 and a72. Amino acids in the two regions have (Whitaker et al 1995) an important role in Hb transformation (Srinivasan and Rose 1994). The second and third d N /d S peaks in bats are located in the two b-turns, and the changes apparent in bats may be involved in Hb transformation.…”

Section: Discussionmentioning

confidence: 99%

Molecular Cloning and Evolutionary Analysis of Hemoglobin α-Chain Genes in Bats

et al. 2009

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Bats are the only mammals with the capacity for powered flight. When flying, they need abundant energy and oxygen. According to previous works, the hemoglobin (Hb) oxygen loading function of bats is insensitive to variations in body temperature, although different bat species have different heat sensitivity. We cloned Hb alpha-chain sequences from eight bat species to investigate whether they have different characteristics. We found that Hb in the bat lineages is under purifying selection, which accords with the importance of its function in bats. Three turn regions in bat Hb, however, have distinct evolutionary rates compared with those of other mammals, and the codons in these regions have an accelerated rate of evolution. These codons are under divergent selection in bats. These changes in Hb may have occurred in response to the physiological requirements of the species concerned, as adaptations to different lifestyles.

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The D-Helix in Myoglobin and in the .beta. Subunit of Hemoglobin Is Required for the Retention of Heme

Cited by 37 publications

References 10 publications

Dissociation of heme-globin complexes by blackbody infrared radiative dissociation: Molecular specificity in the gas phase?

Dissociation of heme-globin complexes by blackbody infrared radiative dissociation: Molecular specificity in the gas phase?

A Rapid Method for Characterization of Protein Relatedness Using Feature Vectors

Molecular Cloning and Evolutionary Analysis of Hemoglobin α-Chain Genes in Bats

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