scholarly journals Purification of the Escherichia coli secB gene product and demonstration of its activity in an in vitro protein translocation system

1989 ◽  
Vol 264 (4) ◽  
pp. 2242-2249 ◽  
Author(s):  
C A Kumamoto ◽  
L Chen ◽  
J Fandl ◽  
P C Tai
Keyword(s):  
Escherichia Coli ◽  
Gene Product ◽  
Protein Translocation ◽  
Vitro Protein

scholarly journals In vitro heme O synthesis by the cyoE gene product from Escherichia coli.

1993 ◽  
Vol 268 (35) ◽  
pp. 26041-26044
Author(s):  
K Saiki ◽  
T Mogi ◽  
K Ogura ◽  
Y Anraku
Keyword(s):  
Escherichia Coli ◽  
Gene Product

scholarly journals Lysyl-tRNA synthetase from Escherichia coli K12. Chromatographic heterogeneity and the lysU-gene product

1987 ◽  
Vol 248 (1) ◽  
pp. 43-51 ◽  
Author(s):  
J Charlier ◽  
R Sanchez
Keyword(s):  
Escherichia Coli ◽  
Gene Product ◽  
Activity Ratio ◽  
Deae Cellulose ◽  
Trna Synthetase ◽  
Trna Synthetases ◽  
E Coli ◽  
Aminoacyl Trna Synthetases

In contrast with most aminoacyl-tRNA synthetases, the lysyl-tRNA synthetase of Escherichia coli is coded for by two genes, the normal lysS gene and the inducible lysU gene. During its purification from E. coli K12, lysyl-tRNA synthetase was monitored by its aminoacylation and adenosine(5′)tetraphospho(5′)adenosine (Ap4A) synthesis activities. Ap4A synthesis was measured by a new assay using DEAE-cellulose filters. The heterogeneity of lysyl-tRNA synthetase (LysRS) was revealed on hydroxyapatite; we focused on the first peak, LysRS1, because of its higher Ap4A/lysyl-tRNA activity ratio at that stage. Additional differences between LysRS1 and LysRS2 (major peak on hydroxyapatite) were collected. LysRS1 was eluted from phosphocellulose in the presence of the substrates, whereas LysRS2 was not. Phosphocellulose chromatography was used to show the increase of LysRS1 in cells submitted to heat shock. Also, the Mg2+ optimum in the Ap4A-synthesis reaction is much higher for LysRS1. LysRS1 showed a higher thermostability, which was specifically enhanced by Zn2+. These results in vivo and in vitro strongly suggest that LysRS1 is the heat-inducible lysU-gene product.

In vitro functional characterization of overproduced Escherichia coli katF/rpoS gene product

Biochemistry ◽  
1993 ◽  
Vol 32 (41) ◽  
pp. 11112-11117 ◽  
Author(s):  
Lam H. Nguyen ◽  
Debra B. Jensen ◽  
Nancy E. Thompson ◽  
Daniel R. Gentry ◽  
Richard R. Burgess
Keyword(s):  
Escherichia Coli ◽  
Gene Product ◽  
Functional Characterization ◽  
Rpos Gene

scholarly journals SecA Dimer Cross-Linked at Its Subunit Interface Is Functional for Protein Translocation

2006 ◽  
Vol 188 (1) ◽  
pp. 335-338 ◽  
Author(s):  
Lucia B. Jilaveanu ◽  
Donald Oliver
Keyword(s):  
Conformational Changes ◽  
Protein Transport ◽  
Protein Translocation ◽  
Directed Mutagenesis ◽  
Subunit Interface ◽  
Cargo Proteins ◽  
Considerable Controversy ◽  
The Subject ◽  
Vitro Protein

ABSTRACT SecA facilitates protein transport across the eubacterial plasma membrane by its association with cargo proteins and the SecYEG translocon, followed by ATP-driven conformational changes that promote protein translocation in a stepwise manner. Whether SecA functions as a monomer or a dimer during this process has been the subject of considerable controversy. Here we utilize cysteine-directed mutagenesis along with the crystal structure of the SecA dimer to create a cross-linked dimer at its subunit interface, which was normally active for in vitro protein translocation.

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