Molecular Shape, Dissociation, and Oxygen Binding of the Dodecamer Subunit of Lumbricus terrestris Hemoglobin
نویسندگان
چکیده
منابع مشابه
Structural basis for cooperative oxygen binding and bracelet-assisted assembly of Lumbricus terrestris hemoglobin
The iron-containing hemoglobins (Hbs) are essential proteins to serve as oxygen transporters in the blood. Among various kinds of Hbs, the earthworm Hbs are the champions in carrying oxygen due to not only their large size but also the unusually high cooperativity of ligand binding. However, the cooperative oxygen binding mechanisms are still mostly unknown. Here we report the cryo-electron mic...
متن کاملA study of the subunit structure of the extracellular hemoglobin of Lumbricus terrestris.
The dissociation of the extracellular hemoglobin of the earthworm Lumbricus terrestris was investigated. At neutral pH, its sz00,~ = 58.9 f 0.2 S and D:o,w = 1.61 f 0.05 X 1O-7 cm2 s-l corresponded to a molecular weight of 3.23 f 0.18 x 106. A minimum molecular weight of 24,000 per heme group was determined from the iron and heme contents, 0.221 f 0.011 weight % and 2.78 =k 0.14 weight %, respe...
متن کاملThe extracellular hemoglobin of the earthworm, Lumbricus terrestris. Determination of subunit stoichiometry.
The giant extracellular hemoglobin of the earthworm, Lumbricus terrestris, has four major O2-binding chains, a, b, and c (forming a disulfide-linked trimer) and d ("monomer"). Participation of additional "linker" chains L1, L2, and L3 is necessary for the assembly of the approximately 3,900+ kDa two-tiered hexagonal structure. We have determined the proportions of linker chains, trimer, and cha...
متن کاملHemoglobin Richmond. Subunit dissociation and oxygen equilibrium properties.
In hemoglobin Richmond (beta102 leads to Lys), amino acid substitution has occurred at the same site as the mutation in hemoglobin Kansas (beta102 Asn leads to Thr), a variant with very low oxygen affinity. Although hemoglobin Richmond has been shown to have increased tetramer-dimer dissociation, its oxygen affinity has been inferred to be normal from studies on hemolysates of carriers. We have...
متن کاملThe binding of hemoglobin to haptoglobin and its relation to subunit dissociation of hemoglobin.
The binding of liganded hemoglobin to haptoglobin, a plasma cr2-glycoprotein, is an irreversible and stoichiometric reaction that occurs physiologically at the micromolar concentration level. The study of the reaction between deoxyhemoglobin which does not bind haptoglobin and a haptoglobin solution saturated with carbon monoxide indicates that hemoglobin tetramer is incapable of binding haptog...
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ژورنال
عنوان ژورنال: Journal of Biological Chemistry
سال: 1996
ISSN: 0021-9258
DOI: 10.1074/jbc.271.31.18695