Crystal structure of oxygenated Scapharca dimeric hemoglobin at 1.7-A resolution.
نویسندگان
چکیده
منابع مشابه
The 2.4-A crystal structure of Scapharca dimeric hemoglobin. Cooperativity based on directly communicating hemes at a novel subunit interface.
The crystal structure of the cooperative dimeric hemoglobin from the arcid clam, Scapharca inaequivalvis, has been determined in the carbonmonoxy state. The phase problem was solved for reflections with Bragg spacings greater than 3 A using anomalous scattering from the porphyrin iron atoms measured at a single wavelength in combination with molecular averaging. The model built into this electr...
متن کاملInsight into the Allosteric Mechanism of Scapharca Dimeric Hemoglobin
Allosteric regulation is an essential function of many proteins that control a variety of different processes such as catalysis, signal transduction, and gene regulation. Structural rearrangements have historically been considered the main means of communication between different parts of a protein. Recent studies have highlighted the importance, however, of changes in protein flexibility as an...
متن کاملLigand Binding to the Dimeric Hemoglobin from Scapharca inaequivaluis , a Hemoglobin with a Novel Mechanism for
The homodimeric hemoglobin from Scapharca inaequivalvis has an unusual spatial arrangement of the subunits (Royer, W. E., Jr., Love, W. E., and Fenderson, F. F. (1986) Nature 316, 277-280). The time course of oxygen and nitric oxide rebinding to this protein following flash photolysis has been measured on a nanosecond time scale. A large amplitude is observed with a half-time of 20 ns (NO). Wit...
متن کاملOxidized Dimeric Scapharca inaequivalvis
The dimeric hemoglobin isolated from Scapharca inaequivalvis, HbI, is notable for its highly cooperative oxygen binding and for the unusual proximity of its heme groups. We now report that the oxidized protein, an equilibrium mixture of a dimeric high spin aquomet form and a monomeric low spin hemichrome, binds ferrocyanide tightly which allows for internal electron transfer with the heme iron....
متن کاملCrystal structure of a nonsymbiotic plant hemoglobin.
BACKGROUND Nonsymbiotic hemoglobins (nsHbs) form a new class of plant proteins that is distinct genetically and structurally from leghemoglobins. They are found ubiquitously in plants and are expressed in low concentrations in a variety of tissues including roots and leaves. Their function involves a biochemical response to growth under limited O(2) conditions. RESULTS The first X-ray crystal...
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ژورنال
عنوان ژورنال: Journal of Biological Chemistry
سال: 1994
ISSN: 0021-9258
DOI: 10.1016/s0021-9258(18)47241-9