scholarly journals Transcriptional Regulation of the Outer Membrane Porin Gene ompW Reveals its Physiological Role during the Transition from the Aerobic to the Anaerobic Lifestyle of Escherichia coli

2016 ◽  
Vol 7 ◽  
Author(s):  
Minfeng Xiao ◽  
Yong Lai ◽  
Jian Sun ◽  
Guanhua Chen ◽  
Aixin Yan
Keyword(s):  
Escherichia Coli ◽  
Transcriptional Regulation ◽  
Outer Membrane ◽  
Physiological Role ◽  
Outer Membrane Porin

Overexpression of parathion hydrolase in Escherichia coli stimulates the synthesis of outer membrane porin OmpF

2006 ◽  
Vol 86 (3) ◽  
pp. 146-150 ◽  
Author(s):  
Dayananda Siddavattam ◽  
Elisha R. Raju ◽  
P.V. Emmanuel Paul ◽  
Mike Merrick
Keyword(s):  
Escherichia Coli ◽  
Outer Membrane ◽  
Outer Membrane Porin ◽  
Parathion Hydrolase

scholarly journals Outer and Inner Membrane Proteins Compose an Arginine-Agmatine Exchange System in Chlamydophila pneumoniae

2008 ◽  
Vol 190 (22) ◽  
pp. 7431-7440 ◽  
Author(s):  
Conor B. Smith ◽  
David E. Graham
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Cytoplasmic Membrane ◽  
Physiological Role ◽  
Arginine Decarboxylase ◽  
Chlamydophila Pneumoniae ◽  
Evolutionary Analysis ◽  
Exchange System ◽  
E Coli ◽  
Outer Membrane Porin

ABSTRACT Most chlamydial strains have a pyruvoyl-dependent decarboxylase protein that converts l-arginine to agmatine. However, chlamydiae do not produce arginine, so they must import it from their host. Chlamydophila pneumoniae has a gene cluster encoding a putative outer membrane porin (CPn1033 or aaxA), an arginine decarboxylase (CPn1032 or aaxB), and a putative cytoplasmic membrane transporter (CPn1031 or aaxC). The aaxC gene was expressed in Escherichia coli producing an integral cytoplasmic membrane protein that catalyzed the exchange of l-arginine for agmatine. Expression of the aaxA gene produced an outer membrane protein that enhanced the arginine uptake and decarboxylation activity of cells coexpressing aaxB and aaxC. This chlamydial arginine/agmatine exchange system complemented an E. coli mutant missing the native arginine-dependent acid resistance system. These cells survived extreme acid shock in the presence of l-arginine. Biochemical and evolutionary analysis showed the aaxABC genes evolved convergently with the enteric arginine degradation system, and they could have a different physiological role in chlamydial cells. The chlamydial system uniquely includes an outer membrane porin, and it is most active at a higher pH from 3 to 5. The chlamydial AaxC transporter was resistant to cadaverine, l-lysine and l-ornithine, which inhibit the E. coli AdiC antiporter.

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