Linked Life Data

11254387

Source:http://linkedlifedata.com/resource/pubmed/id/11254387

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2001-3-20
pubmed:abstractText
The gp41 envelope protein mediates the entry of primate immunodeficiency viruses into target cells by promoting the fusion of viral and cellular membranes. The structure of the gp41 ectodomain core represents a trimer of identical helical hairpins in which a central trimeric coiled-coil made up of three amino-terminal helices is wrapped in an outer layer of three antiparallel carboxyl-terminal helices. Triggering formation of this fusion-active gp41 conformation appears to cause close membrane apposition and thus overcome the activation energy barrier for lipid bilayer fusion. We present a detailed description of the folding thermodynamics of the simian immunodeficiency virus (SIV) gp41 core by using a recombinant trimeric N34(L6)C28 model. Differential scanning calorimetry and spectroscopic experiments on denaturant-induced and thermal unfolding indicate that the free energy of association of three 68 residue N34(L6)C28 peptides to a trimer-of-hairpins is 76 kJ mol(-1) at pH 7.0 and 25 degrees C in physiological buffer. The associated enthalpy change, Delta H(unf), is 177 kJ mol(-1), while the entropy of unfolding, Delta S(unf), is 0.32 kJ K(-1) mol(-1). The temperature of maximal stability is close to 20 degrees C. The unfolding heat capacity increment is approximately 9 kJ K(-1) mol(-1) (approximately 45 J K(-1) mol residue(-1)), which is lower than expected for unfolding of the trimer to an extended and fully hydrated polypeptide chain. Replacement by isoleucine of the polar residues Thr582 or Thr586 buried in the N-terminal trimeric coiled-coil interface leads to very strong stabilization of the trimer-of-hairpins, 30-35 kJ mol(-1). Single-point mutations in the central coiled-coil thus strongly stabilize the gp41 core structure. These thermodynamic characteristics may be important for the refolding of the gp41 envelope protein into its fusion-active conformation during membrane fusion.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0022-2836
pubmed:author
pubmed:copyrightInfo
Copyright 2001 Academic Press.
pubmed:issnType
Print
pubmed:day
23
pubmed:volume
307
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
637-56
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed-meshheading:11254387-Amino Acid Sequence, pubmed-meshheading:11254387-Artifacts, pubmed-meshheading:11254387-Calorimetry, Differential Scanning, pubmed-meshheading:11254387-Circular Dichroism, pubmed-meshheading:11254387-Computer Simulation, pubmed-meshheading:11254387-Membrane Glycoproteins, pubmed-meshheading:11254387-Models, Molecular, pubmed-meshheading:11254387-Models, Theoretical, pubmed-meshheading:11254387-Molecular Sequence Data, pubmed-meshheading:11254387-Mutation, pubmed-meshheading:11254387-Peptide Fragments, pubmed-meshheading:11254387-Protein Denaturation, pubmed-meshheading:11254387-Protein Folding, pubmed-meshheading:11254387-Protein Structure, Quaternary, pubmed-meshheading:11254387-Protein Structure, Secondary, pubmed-meshheading:11254387-Recombinant Proteins, pubmed-meshheading:11254387-Retroviridae Proteins, pubmed-meshheading:11254387-Simian immunodeficiency virus, pubmed-meshheading:11254387-Spectrometry, Fluorescence, pubmed-meshheading:11254387-Thermodynamics, pubmed-meshheading:11254387-Viral Envelope Proteins
pubmed:year
2001
pubmed:articleTitle
Thermodynamics of trimer-of-hairpins formation by the SIV gp41 envelope protein.
pubmed:affiliation
Biochemisches Institut der Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland. iljel@bioc.unizh.ch
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't