Linked Life Data

2592366

Source:http://linkedlifedata.com/resource/pubmed/id/2592366

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
35
pubmed:dateCreated
1990-1-19
pubmed:abstractText
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 electron density map has been refined at 2.4 A resolution by means of stereochemically restrained least squares minimization to a conventional R-value of 0.156. The root mean square deviation from ideal bond lengths and angles are 0.013 A and 1.7 degrees, respectively. In addition to the 2336 hemoglobin atoms, 214 water molecules have been incorporated into the model. This structure reveals the details of an assemblage of two identical myoglobin-like subunits that is radically different from vertebrate hemoglobins. The subunit interface is formed by direct apposition of the E and F helices, whereas these surfaces are external in vertebrate hemoglobins. The interface has both hydrophobic and hydrophilic character. Two symmetrically related hydrophobic regions are formed between subunits. Six residues are involved in each of these regions that pack tightly enough to exclude water but have only a few atoms in close van der Waals contact. A number of ordered water molecules line the interface and form bridging hydrogen bonds between subunits. Four intersubunit ionic interactions are formed, two of which involve negatively charged propionate groups of the porphyrin. In contrast to cooperative vertebrate hemoglobins, a hydrogen bond network provides a direct route for communication between the two heme groups.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
264
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
21052-61
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1989
pubmed:articleTitle
The 2.4-A crystal structure of Scapharca dimeric hemoglobin. Cooperativity based on directly communicating hemes at a novel subunit interface.
pubmed:affiliation
Howard Hughes Medical Institute, Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York 10032.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S.