Linked Life Data

10985768

Source:http://linkedlifedata.com/resource/pubmed/id/10985768

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
37
pubmed:dateCreated
2000-10-19
pubmed:abstractText
Factors governing the folding pathways and the stability of apomyoglobin have been examined by replacing the distal histidine at position 64 with phenylalanine (H64F). Acid and urea-induced unfolding experiments using CD and fluorescence techniques reveal that the mutant H64F apoprotein is significantly more stable than wild-type apoMb. Kinetic refolding studies of this variant also show a significant difference from wild-type apoMb. The amplitude of the burst phase ellipticity in stopped-flow CD measurements is increased over that of wild-type, an indication that the secondary structure content of the earliest kinetic intermediate is greater in the mutant than in the wild-type protein. In addition, the overall rate of folding is markedly increased. Hydrogen exchange pulse labeling was used to establish the structure of the initial intermediate formed during the burst phase of the H64F mutant. NMR analysis of the samples obtained at different refolding times indicates that the burst phase intermediate contains a stabilized E helix as well as the A, G, and H helices previously found in the wild-type kinetic intermediate. Replacement of the polar distal histidine residue with a nonpolar residue of similar size and shape appears to stabilize the E helix in the early stages of folding due to improved hydrophobic packing. The presence of a hydrophilic histidine at position 64 thus exacts a price in the stability and folding efficiency of the apoprotein, but this residue is nevertheless highly conserved among myoglobins due to its importance in function.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
19
pubmed:volume
39
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
11227-37
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed-meshheading:10985768-Amino Acid Substitution, pubmed-meshheading:10985768-Animals, pubmed-meshheading:10985768-Apoproteins, pubmed-meshheading:10985768-Circular Dichroism, pubmed-meshheading:10985768-Histidine, pubmed-meshheading:10985768-Hydrogen-Ion Concentration, pubmed-meshheading:10985768-Kinetics, pubmed-meshheading:10985768-Mutagenesis, Site-Directed, pubmed-meshheading:10985768-Myoglobin, pubmed-meshheading:10985768-Nuclear Magnetic Resonance, Biomolecular, pubmed-meshheading:10985768-Phenylalanine, pubmed-meshheading:10985768-Protein Conformation, pubmed-meshheading:10985768-Protein Folding, pubmed-meshheading:10985768-Protein Structure, Secondary, pubmed-meshheading:10985768-Spectrometry, Fluorescence, pubmed-meshheading:10985768-Thermodynamics, pubmed-meshheading:10985768-Whales
pubmed:year
2000
pubmed:articleTitle
Changes in the apomyoglobin folding pathway caused by mutation of the distal histidine residue.
pubmed:affiliation
Department of Molecular Biology and Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037, USA.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't