Linked Life Data

7775472

Source:http://linkedlifedata.com/resource/pubmed/id/7775472

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
23
pubmed:dateCreated
1995-7-10
pubmed:abstractText
Transmembrane segments of proteins generally consist of a long stretch of hydrophobic amino acids, which can function to initiate membrane insertion (start-stop sequences), initiate translocation (signal-anchor sequences), or stop further translocation of the following polypeptide chain (stop-transfer sequences). In this study, we have taken Escherichia coli alkaline phosphatase, a transported and water-soluble protein, and examined the requirements for converting it into a transmembrane protein with particular orientation. Since the wild type enzyme is transported, there is no predisposition against membrane translocation, yet it is not a membrane protein, so it does not possess any intrinsic membrane topogenic preferences. A series of potential transmembrane segments was introduced into an internal position of the enzyme to test the ability of each to initiate translocation, stop translocation, and adopt a particular orientation. For this purpose, cassette mutagenesis was used to incorporate new structural segments composed of polymers of alanines and leucines. The threshold value of hydrophobicity required to function as a stop-transfer sequence was determined. For a transmembrane segment of typical length (21 residues), this value is equivalent to the hydrophobicity of 16 alanines and 5 leucines. Interestingly, much shorter segments will also suffice to stop translocation, but these must be composed of more highly hydrophobic residues (e.g. 11 leucines). When the wild type amino-terminal signal peptide is deleted or made dysfunctional, sufficiently hydrophobic internal segments can initiate translocation of the following polypeptide and function as a signal anchor. Furthermore, in so doing, the orientation of the protein is changed from N(out)-C(in) to N(in)-C(out).
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
9
pubmed:volume
270
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
14115-22
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Artificial transmembrane segments. Requirements for stop transfer and polypeptide orientation.
pubmed:affiliation
Department of Molecular and Cell Biology, University of Connecticut, Storrs 06269, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.