Linked Life Data

18190529

Source:http://linkedlifedata.com/resource/pubmed/id/18190529

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2008-1-31
pubmed:abstractText
Campylobacter jejuni hosts two hemoglobins (Hbs). The Camplylobacter jejuni single-domain Hb (called Cgb) is homologous to the globin domain of flavohemoglobin, and it has been proposed to protect the bacterium against nitrosative stress. The second Hb is called Ctb (hereafter Cj-trHbP), belongs to truncated Hb group III, and has been hypothesized to be involved in O(2) chemistry. Here, the kinetics and thermodynamics of cyanide binding to ferric and ferrous Cj-trHbP [Cj-trHbP(III) and Cj-trHbP(II), respectively] are reported and analyzed in parallel with those of related heme proteins, with particular reference to those from Mycobacterium tuberculosis. The affinity of cyanide for Cj-trHbP(II) is higher than that reported for any known (in)vertebrate globin by more than three orders of magnitude (K = 1.2 x 10(-6) m). This can be fully attributed to the highest (ever observed for a ferrous Hb) cyanide-binding association rate constant (k(on) = 3.3 x 10(3) m(-1).s(-1)), even though the binding process displays a rate-limiting step (k(max) = 9.1 s(-1)). Cj-trHbP(III) shows a very high affinity for cyanide (L = 5.8 x 10(-9) m); however, cyanide association kinetics are independent of cyanide concentration, displaying a rate-limiting step (l(max) = 2.0 x 10(-3) s(-1)). Values of the first-order rate constant for cyanide dissociation from Cj-trHbP(II)-cyanide and Cj-trHbP(III)-cyanide (k(off) =5.0 x 10(-3) s(-1) and l(off) > or = 1 x 10(-4) s(-1), respectively) are similar to those reported for (in)vertebrate globins. The very high affinity of cyanide for Cj-trHbP(II), reminiscent of that of horseradish peroxidase(II), suggests that this globin may participate in cyanide detoxification.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
1742-464X
pubmed:author
pubmed:issnType
Print
pubmed:volume
275
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
633-45
pubmed:meshHeading
pubmed:year
2008
pubmed:articleTitle
Ferrous Campylobacter jejuni truncated hemoglobin P displays an extremely high reactivity for cyanide - a comparative study.
pubmed:affiliation
Dipartimento di Biologia, Università Roma Tre, Italy.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't, Research Support, N.I.H., Extramural