The dissociation of the extracellular hemoglobin of Lumbricus terrestris at acid pH and its reassociation at neutral pH. A new model of its quaternary structure.

Mainwaring, Mark G.; Lugo, Stephen D.; Fingal, R A; Kapp, Oscar H.; Vinogradov, Serge N.

doi:10.1016/s0021-9258(18)67472-1

Cited by 55 publications

(4 citation statements)

References 29 publications

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“…Following the determination of the smallest subunits and number of polypeptide chains by complete dissociation of Lumbricus Hb, we sought to identify larger subunits via partial dissociation of the HBL structure, at pH > 8, at pH < 6, and at neutral pH in the presence of urea, Gdm·Cl, and chaotropic agents. , These studies provided unequivocal evidence for a functional ∼2 × 10 5 subunit having the stoichiometry [ a + b + c ] 3 [ d 3 ], deficient in linker chains and which could be formed spontaneously upon mixing of the isolated trimer [ a + b + c ] and chain d − A recent study of the dissociation kinetics of Lumbricus Hb at alkaline pH and at neutral pH in the presence of urea, Gdm salts, and heteropolytungstate cations has demonstrated that the dodecamer is observed at all stages of the dissociation, the extent of dissociation decreasing in the order Gdm·SCN > Gdm·Cl > urea > Gdm·OAc and [BaAs 4 W 40 O 140 ] 27- > [SiW 11 O 39 ] 8- > [NaSb 9 W 21 O 86 ] 18- .…”

Section: Dissociation Defines a Hierarchy Of Globin Subunitsmentioning

confidence: 99%

“…17 The pogonophoran Oligobrachia Hb appears to comprise monomers and disulfide-bonded dimers and trimers of globin chains. 40 Following the determination of the smallest subunits and number of polypeptide chains by complete dissociation of Lumbricus Hb, we sought to identify larger subunits via partial dissociation of the HBL structure, at pH > 8, 43 at pH < 6, 44 and at neutral pH in the presence of urea, Gdm‚Cl, and chaotropic agents. 45,46 These studies provided unequivocal evidence for a functional ∼2 × 10 5 subunit having the stoichiometry [a+b+c] 3 [d 3 ], deficient in linker chains and which could be formed spontaneously upon mixing of the isolated trimer [a+b+c] and chain d. 46 Under similar conditions, the leech (Macrobdella) Hb produced a tetramer of globin chains and Eudistylia Chl dissociated into dodecamers and tetramers in equilibrium with each other.…”

Section: B Iron Heme and Carbohydrate Contentsmentioning

confidence: 99%

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Giant Hexagonal Bilayer Hemoglobins

et al. 1996

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Section: Dissociation Defines a Hierarchy Of Globin Subunitsmentioning

confidence: 99%

Section: B Iron Heme and Carbohydrate Contentsmentioning

confidence: 99%

Giant Hexagonal Bilayer Hemoglobins

et al. 1996

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“…Indeed, AlVinella would not be the only species possessing hemecontaining linker chains in its Hb. The linker chain L2 of Lumbricus Hb also binds heme (Mainwaring et al, 1986;Ownby et al, 1993;Martin et al, 1996).…”

Section: Cysteine Contents and Sulfide Bindingmentioning

confidence: 99%

Investigation by Electrospray Ionization Mass Spectrometry of the Extracellular Hemoglobin from the Polychaete Annelid Alvinella pompejana: An Unusual Hexagonal Bilayer Hemoglobin

et al. 1997

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Alvinella pompejana inhabits deep-sea hydrothermal vent sites along the East-Pacific Rise, where it colonizes the walls of actively venting high-temperature chimneys. This worm is the most thermophilic metazoan known to date. In Alvinella, as in other alvinellids, oxygen transport is mainly achieved by an extracellular Hb dissolved in the vascular blood. This Hb has a molecular mass of 3833 +/- 14 kDa as revealed by multiangle laser light scattering (MALLS). Native and derivative Hb (reduced, carbamidomethylated, and deglycosylated) were analyzed by electrospray ionization mass spectrometry (ESI-MS). The data were processed by the maximum entropy deconvolution system (MaxEnt). We identified three groups of peaks for Alvinella Hb, at ca. 16, 23-26, and 50 kDa corresponding to (i) four monomeric globin chains, a1 (16 633.4), a2(16 532.4), a3 (16 419.6), and a4(16 348.9); (ii) four linker chains, L1-L4 (22 887. 1, 24 230.5, 26 233.6, and 25 974.4); and (iii) one disulfide-bonded trimer T (51 431.9) composed of globin chains b (16 477.5), c (16 916.1), and d (18 048.8). These Hbs were also subjected to SDS-PAGE analysis for comparative purposes. In addition, using the ESI-MS data we propose two alternative models for the quaternary structure of Alvinella's Hb.

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“…The dissociation behavior of L.t. Hb was investigated at extremes of pH and in the presence of several dissociating agents (e.g., [6,7,[22][23][24]). A variety of dissociation and re-association experiments resulted in the observation of a 9-10 S species which was considered to represent one-twelfth protomer, an approx.…”

Section: Introductionmentioning

confidence: 99%

Modeling of the Dodecameric Subunit of Lumbricus Hemoglobin

Zipper

Durchschlag

Krebs

Analytical Ultracentrifugation VIII

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For modeling the lowresolution shape of the dodecameric subunit of Lumbricus terrestris hemoglobin, experimental smallangle X-ray scattering (SAXS) data and ab initio modeling approaches using a genetic algorithm or simulated annealing have been applied. In addition to the use of strict ab initio approaches, procedures which additionally include available structural information concerning symmetry and shape in the form of constraints or templates have been employed to improve the results. Templates for the subunit were preferably derived from SAXS-based models for the native hexagonal bilayer (HBL) complex that were biased by electron microscopic reconstructions. The obtained subunit models were carefully examined by variation of different selection and averaging methods and other checks such as surface renderings of the models. The findings were quantified by prediction of scattering profiles, I(h) and p(r), and structural and hydrodynamic parameters (V , R G , d max , s, D). The best matching models for the subunit were also scrutinized by comparing them to a model derived from currently available crystallographic data. The following results could be obtained: (i) The obtained parameter predictions for the dodecameric subunit are satisfactory, if compared to the SAXS data (consensus model, profiles and molecular parameters) or the results from hydrodynamic studies. (ii) The comparison between solution and crystal data of the dodecameric subunit, however, unequivocally proves a different behavior of the subunit in solution and the crystalline state.

show abstract

The dissociation of the extracellular hemoglobin of Lumbricus terrestris at acid pH and its reassociation at neutral pH. A new model of its quaternary structure.

Cited by 55 publications

References 29 publications

Giant Hexagonal Bilayer Hemoglobins

Giant Hexagonal Bilayer Hemoglobins

Investigation by Electrospray Ionization Mass Spectrometry of the Extracellular Hemoglobin from the Polychaete Annelid Alvinella pompejana: An Unusual Hexagonal Bilayer Hemoglobin

Modeling of the Dodecameric Subunit of Lumbricus Hemoglobin

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