scholarly journals Heterologous complementation studies in Escherichia coli with the Hyp accessory protein machinery from Chloroflexi provide insight into [NiFe]-hydrogenase large subunit recognition by the HypC protein family

Microbiology ◽  
2015 ◽  
Vol 161 (11) ◽  
pp. 2204-2219 ◽  
Author(s):  
Stefanie Hartwig ◽  
R. Gary Sawers ◽  
Nadya Krumova ◽  
Dominique Türkowsky ◽  
Vivien Quitzke ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Large Subunit ◽  
Protein Family ◽  
Accessory Protein ◽  
Heterologous Complementation ◽  
Insight Into

scholarly journals The Extended C-Terminal α-Helix of the HypC Chaperone Restricts Recognition of Large Subunit Precursors by the Hyp-Scaffold Machinery during [NiFe]-Hydrogenase Maturation in Escherichia coli

2018 ◽  
Vol 28 (2) ◽  
pp. 87-97
Author(s):  
Claudia Thomas ◽  
Mandy Waclawek ◽  
Kerstin Nutschan ◽  
Constanze Pinske ◽  
R. Gary Sawers
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Large Subunit ◽  
Protein Family ◽  
Variable Regions ◽  
E Coli ◽  
Hydrogenase Maturation ◽  
C Terminus ◽  
Α Helix

Members of the HypC protein family are chaperone-like proteins that play a central role in the maturation of [NiFe]-hydrogenases (Hyd). <i>Escherichia coli</i> has a second copy of HypC, called HybG, and, as a component of the HypDEF maturation scaffold, these proteins help synthesize the NiFe-cofactor and guide the scaffold to its designated hydrogenase large subunit precursor. HypC is required to synthesize active Hyd-1 and Hyd-3, while HybG facilitates Hyd-2 and Hyd-1 synthesis. To identify determinants on HypC that allow it to discriminate against Hyd-2, we made amino acid exchanges in 3 variable regions, termed VR1, VR2, and VR3, of HypC, that make it more similar to HybG. Region VR3 includes a HypC-specific C-terminal α-helical extension, and this proved particularly important in preventing the maturation of Hyd-2 by HypC. Truncation of this extension on HypC increased Hyd-2 activity in the absence of HybG, while retaining maturation of Hyd-3 and Hyd-1. Combining this truncation with amino acid exchanges in VR1 and VR2 of HypC negatively affected the synthesis of active Hyd-1. The C-terminus of <i>E. coli</i> HypC is thus a key determinant in hindering Hyd-2 maturation, while VR1 and VR2 appear more important for Hyd-1 matu­ration.

scholarly journals Escherichia coli exonuclease VII. Cloning and sequencing of the gene encoding the large subunit (xseA).

1986 ◽  
Vol 261 (32) ◽  
pp. 14929-14935
Author(s):  
J W Chase ◽  
B A Rabin ◽  
J B Murphy ◽  
K L Stone ◽  
K R Williams
Keyword(s):  
Escherichia Coli ◽  
Large Subunit ◽  
Cloning And Sequencing ◽  
Gene Encoding ◽  
Exonuclease Vii

scholarly journals Chi-Dependent Intramolecular Recombination in Escherichia coli

Genetics ◽  
1998 ◽  
Vol 148 (2) ◽  
pp. 545-557
Author(s):  
Rachel Friedman-Ohana ◽  
Iris Karunker ◽  
Amikam Cohen
Keyword(s):  
Escherichia Coli ◽  
Homologous Recombination ◽  
Experimental System ◽  
Cis Acting ◽  
Enzymes Activity ◽  
Intramolecular Recombination ◽  
Insight Into

Abstract Homologous recombination in Escherichia coli is enhanced by a cis-acting octamer sequence named Chi (5′-GCTGGTGG-3′) that interacts with RecBCD. To gain insight into the mechanism of Chi-enhanced recombination, we recruited an experimental system that permits physical monitoring of intramolecular recombination by linear substrates released by in vivo restriction from infecting chimera phage. Recombination of the released substrates depended on recA, recBCD and cis-acting Chi octamers. Recombination proficiency was lowered by a xonA mutation and by mutations that inactivated the RuvABC and RecG resolution enzymes. Activity of Chi sites was influenced by their locations and by the number of Chi octamers at each site. A single Chi site stimulated recombination, but a combination of Chi sites on the two homologs was synergistic. These data suggest a role for Chi at both ends of the linear substrate. Chi was lost in all recombinational exchanges stimulated by a single Chi site. Exchanges in substrates with Chi sites on both homologs occurred in the interval between the sites as well as in the flanking interval. These observations suggest that the generation of circular products by intramolecular recombination involves Chi-dependent processing of one end by RecBCD and pairing of the processed end with its duplex homolog.

scholarly journals Overproduction of SecA Suppresses the Export Defect Caused by a Mutation in the Gene Encoding the Escherichia coli Export Chaperone SecB

1999 ◽  
Vol 181 (10) ◽  
pp. 3010-3017 ◽  
Author(s):  
Heather A. Cook ◽  
Carol A. Kumamoto
Keyword(s):  
Escherichia Coli ◽  
Outer Membrane Proteins ◽  
Protein A ◽  
In Vivo Studies ◽  
Wild Type ◽  
Gene Encoding ◽  
Precursor Proteins ◽  
Additional Support ◽  
Insight Into

ABSTRACT SecB is a cytosolic protein required for rapid and efficient export of particular periplasmic and outer membrane proteins inEscherichia coli. SecB promotes export by stabilizing newly synthesized precursor proteins in a nonnative conformation and by targeting the precursors to the inner membrane. Biochemical studies suggest that SecB facilitates precursor targeting by binding to the SecA protein, a component of the membrane-embedded translocation apparatus. To gain more insight into the functional interaction of SecB and SecA, in vivo, mutations in the secA locus that compensate for the export defect caused by the secBmissense mutation secBL75Q were isolated. Two suppressors were isolated, both of which led to the overproduction of wild-type SecA protein. In vivo studies demonstrated that the SecBL75Q mutant protein releases precursor proteins at a lower rate than does wild-type SecB. Increasing the level of SecA protein in the cell was found to reverse this slow-release defect, indicating that overproduction of SecA stimulates the turnover of SecBL75Q-precursor complexes. These findings lend additional support to the proposed pathway for precursor targeting in which SecB promotes targeting to the translocation apparatus by binding to the SecA protein.

Structure-function studies of the large subunit of ribonucleotide reductase from Escherichia coli

1988 ◽  
Vol 16 (2) ◽  
pp. 91-94 ◽  
Author(s):  
OLLE NILSSON ◽  
TOMAS LUNDQVIST ◽  
SOLVEIG HAHNE ◽  
BRITT-MARIE SJÖBERG
Keyword(s):  
Escherichia Coli ◽  
Structure Function ◽  
Ribonucleotide Reductase ◽  
Large Subunit
Sign in / Sign up

Export Citation Format

Share Document