Linked Life Data

8347573

Source:http://linkedlifedata.com/resource/pubmed/id/8347573

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
30
pubmed:dateCreated
1993-9-10
pubmed:abstractText
Chlorocruorin is a cooperative respiratory pigment found in the blood of polychaete worms; its prosthetic group is a derivative of the iron protoporphyrin IX, in which the vinyl group at position 2 is substituted by a formyl group. The quaternary structure of chlorocruorins is complex: myoglobin-like subunits are grouped in tetramers and tetramers in dodecamers; 12 dodecamers are assembled in the 3500-kDa particle. Chlorocruorin from Spirographis spallanzanii displays the following overall functional properties: (i) the oxygen affinity is lower than in human hemoglobin, while that of CO is similar if not higher; (ii) the rates of combination with oxygen and carbon monoxide are low; and (iii) the off rate of oxygen is comparable to that of human hemoglobin, while the off rate of CO is 10 times smaller. When CO is partially photolyzed with a long and powerful light flash (70 microseconds), rebinding is biphasic as in mammalian hemoglobins; however, the slowest rate is faster than that observed by stopped flow, suggesting that the unliganded protein decays from the liganded high affinity state (R) to an intermediate state before reaching the low affinity (T) state. Oxygen binding was followed by stopped-flow and flash photolysis. While partial photolysis yields a fast, second-order time course, stopped-flow experiments yield slow, biphasic, and non-second-order time courses. This pattern of reactivity was attributed to a slow conformational transition(s) which is (are) rare limiting with oxygen, but not with CO.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
3
pubmed:volume
32
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
7635-43
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1993
pubmed:articleTitle
Ligand binding and slow structural changes in chlorocruorin from Spirographis spallanzanii.
pubmed:affiliation
Department of Biochemical Sciences Alessandro Rossi Fanelli, University of Rome, La Sapienza, Italy.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't