Linked Life Data

8827448

Source:http://linkedlifedata.com/resource/pubmed/id/8827448

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
1996-12-17
pubmed:databankReference
pubmed:abstractText
SecE, an essential membrane component of the Escherichia coli protein translocase, consists of 127 amino acid residues. Only a part of the second putative cytoplasmic region comprising some 13 residues is essential for the SecE function as long as the proper topological arrangement is retained. The Trp84 and Pro85 residues of this region are conserved in all eubacterial SecE homologues. The conservation of positively charged residues corresponding to Arg80 and Lys81 is also substantial. We deleted or replaced these residues to assess their roles in the SecE function. Deletion of the Arg80-Lys81 dipeptide did not abolish the SecE function whereas that of Trp84 or Pro85 caused a loss of the function. Strikingly, however, replacement of Pro85 with either Gly, Ser, or Ala, and that of Trp84 with Lys did not abolish the SecE function. These results indicate that the strong conservation of these residues does not reflect their obligatory requirement for the SecE function. A chimeric SecE possessing the cytoplasmic region of the E. coli SecE and the following region of the Bacillus subtilis SecE was able to form the translocation machinery together with SecA, SecY, and SecG. Although a Leu to Arg mutation at position 108 has been thought to cause a loss of signal recognition fidelity and thereby suppress a signal sequence defect, the same mutation at position 111 caused a complete loss of the function. The levels of SecY and SecG in the secEcsE501 mutant, which expresses SecE at a decreased level and is sensitive to low temperature, increased upon the expression of functional SecE derivatives, irrespective of the site of mutation, suggesting that the levels of SecY and SecG are co-operatively determined by the level of functional, but not non-functional, SecE. Based on these results, the SecE function in the translocase is discussed.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0021-924X
pubmed:author
pubmed:issnType
Print
pubmed:volume
119
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1124-30
pubmed:dateRevised
2007-12-19
pubmed:meshHeading
pubmed:year
1996
pubmed:articleTitle
Roles of the conserved cytoplasmic region and non-conserved carboxy-terminal region of SecE in Escherichia coli protein translocase.
pubmed:affiliation
Institute of Molecular and Cellular Biosciences, University of Tokyo.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't