Linked Life Data

8893861

Source:http://linkedlifedata.com/resource/pubmed/id/8893861

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1996-12-5
pubmed:abstractText
The horseshoe crab, Limulus polyphemus, employs hemocyanin as an oxygen carrier in its hemolymph. This hemocyanin displays cooperative oxygen binding and heterotropic allosteric regulation by protons, chloride ions and divalent cations. Here, we report the crystal structure of Limulus polyphemus subunit type II hemocyanin with a nitrate ion bound in the interface of its first and second domains. Interestingly, the nitrate-binding site coincides with the binding site for the allosteric effector chloride. Oxygen-binding data indeed indicate that nitrate, like chloride, reduces the oxygen affinity of this hemocyanin. The observed binding of two distinct anions to a single site suggests that several other anions may also bind at this site. This opens the intriguing possibility that bicarbonate, which is structurally similar to nitrate and closely linked to respiration, can act as an allosteric effector that lowers the oxygen affinity. Such an effect could be another factor in the repertoire of allosteric regulators of this hemocyanin; however, the physiological implications will be a challenge to decipher, since there exists a complex interplay of effects between bicarbonate, chloride, pH and divalent cations.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0022-2836
pubmed:author
pubmed:issnType
Print
pubmed:day
4
pubmed:volume
262
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
532-41
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1996
pubmed:articleTitle
Nitrate binding to Limulus polyphemus subunit type II hemocyanin and its functional implications.
pubmed:affiliation
Department of Chemical Physics, University of Groningen, AG, The Netherlands.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't