Linked Life Data

2071577

Source:http://linkedlifedata.com/resource/pubmed/id/2071577

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
20
pubmed:dateCreated
1991-8-19
pubmed:abstractText
We have previously demonstrated that a synthetic gene encoding Cerebratulus lacteus neurotoxin B-IV can be expressed in bacteria, and the recombinant toxin purified and refolded (Howell, M. L., and Blumenthal, K. M. (1989) J. Biol. Chem. 264, 15268-15273). This toxin, which contains an NH2-terminal methionine residue not present in authentic B-IV, has a specific toxicity 35-40% that of the naturally occurring form. Deletion of the codon for the NH2-terminal methionine allows expression of fully active recombinant B-IV, demonstrating that hydroxylation of Pro-10 is not important for biological activity. Site-directed mutagenesis of the des-Met(-1) form has been employed to analyze the contribution of NH2-terminal sequences of this toxin to its activity. We have emphasized replacement of helix-favoring residues by helix-destabilizing ones which are otherwise sterically similar. When Ala-3 or Ala-8 is replaced by serine, little or no effect on specific toxicity is observed. However, the double mutant in which both alanines are substituted with serine is more than twice as active as natural B-IV, although the secondary structures and conformational stabilities of the wild-type and mutant forms are the same. When Ala-3 and 8 are simultaneously replaced with glycine, the resulting toxin displays an activity similar to that of the wild-type form. The conformational properties of this mutant are unchanged from that of either wild-type or the serine double mutant. These data indicate that insertion into the NH2-terminal region of toxin B-IV of residues which can participate in hydrogen bond formation enhances biological activity of the protein.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
266
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
12884-8
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1991
pubmed:articleTitle
Mutagenesis of Cerebratulus lacteus neurotoxin B-IV identifies NH2-terminal sequences important for biological activity.
pubmed:affiliation
Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati College of Medicine, Ohio 45267-0524.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S.