Linked Life Data

18187151

Source:http://linkedlifedata.com/resource/pubmed/id/18187151

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2008-2-5
pubmed:abstractText
Despite the widespread presence of the globin fold in most living organisms, only eukaryotic globins have been employed as model proteins in folding/stability studies so far. This work introduces the first thermodynamic and kinetic characterization of a prokaryotic globin, that is, the apo form of the heme-binding domain of flavohemoglobin (apoHmpH) from Escherichia coli. This bacterial globin has a widely different sequence but nearly identical structure to its eukaryotic analogues. We show that apoHmpH is a well-folded monomeric protein with moderate stability at room temperature [apparent Delta G degrees (UN(w))=-3.1+/-0.3 kcal mol(-1); m(UN)=-1.7 kcal mol(-1) M(-1)] and predominant alpha-helical structure. Remarkably, apoHmpH is the fastest-folding globin known to date, as it refolds about 4- to 16-fold more rapidly than its eukaryotic analogues (e.g., sperm whale apomyoglobin and soybean apoleghemoglobin), populating a compact kinetic intermediate (beta(I)=0.9+/-0.2) with significant helical content. Additionally, the single Trp120 (located in the native H helix) becomes locked into a fully native-like environment within 6 ms, suggesting that this residue and its closest spatial neighbors complete their folding at ultrafast (submillisecond) speed. In summary, apoHmpH is a bacterial globin that shares the general folding scheme (i.e., a rapid burst phase followed by slower rate-determining phases) of its eukaryotic analogues but displays an overall faster folding and a kinetic intermediate with some fully native-like traits. This study supports the view that the general folding features of bacterial and eukaryotic globins are preserved through evolution while kinetic details differ.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
1089-8638
pubmed:author
pubmed:issnType
Electronic
pubmed:day
22
pubmed:volume
376
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
879-97
pubmed:meshHeading
pubmed:year
2008
pubmed:articleTitle
Thermodynamic and kinetic characterization of apoHmpH, a fast-folding bacterial globin.
pubmed:affiliation
Department of Biochemistry, University of Wisconsin-Madison, 433 Babcock Drive, Madison, WI 53706, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't