Alternative respiratory pathways of Escherichia coli: Energetics and transcriptional regulation in response to electron acceptors

被引:521
作者
Unden, G
Bongaerts, J
机构
[1] Inst. Mikrobiol. und Weinforschung, Universität Mainz, 55099 Mainz
来源
BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS | 1997年 / 1320卷 / 03期
关键词
aerobic electron transport; anaerobic electron transport; regulation; FNR; ArcA; oxygen sensor; (Escherichia coli);
D O I
10.1016/S0005-2728(97)00034-0
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
The electron-transport chains of Escherichia coli are composed of many different dehydrogenases and terminal reductases (or oxidases) which are linked by quinones (ubiquinone, menaquinone and demethylmenaquinone). Quinol:cytochrome c oxido-reductase ('bc(1) complex') is not present. For various electron accepters (O-2, nitrate) and donors (formate, H-2, NADH, glycerol-3-P) isoenzymes are present. The enzymes show great variability in membrane topology and energy conservation. Energy is conserved by conformational proton pumps, or by arrangement of substrate sites on opposite sides of the membrane resulting in charge separation. Depending on the enzymes and isoenzymes used, the H+/e(-) ratios are between 0 and 4 H+/e(-) for the overall chain. The expression of the terminal reductases is regulated by electron accepters. O-2 is the preferred electron acceptor and represses the terminal reductases of anaerobic respiration. In anaerobic respiration, nitrate represses other terminal reductases, such as fumarate or DMSO reductases. Energy conservation is maximal with O-2 and lowest with fumarate. By this regulation pathways with high ATP or growth yields are favoured. The expression of the dehydrogenases is regulated by the electron accepters, too. In aerobic growth, non-coupling dehydrogenases are expressed and used preferentially, whereas in fumarate or DMSO respiration coupling dehydrogenases are essential. Coupling and non-coupling isoenzymes are expressed correspondingly. Thus the rationale for expression of the dehydrogenases is not maximal energy yield, but could be maximal flux or growth rates. Nitrate regulation is effected by two-component signal transfer systems with membraneous nitrate/nitrite sensors (NarX, NarQ) and cytoplasmic response regulators (NarL, NarP) which communicate by protein phosphorylation. O-2 regulates by a two-component regulatory system consisting of a membraneous sensor (ArcB) and a response regulator (ArcA). ArcA is the major regulator of aerobic metabolism and represses the genes of aerobic metabolism under anaerobic conditions. FNR is a cytoplasmic O-2 responsive regulator with a sensory and a regulatory DNA-binding domain. FNR is the regulator of genes required for anaerobic respiration and related pathways. The binding sites of NarL, NarP, ArcA and FNR are characterized for various promoters. Most of the genes are regulated by more than one of the regulators, which can act in any combination and in a positive or negative mode. By this the hierarchical expression of the genes in response to the electron acceptors is achieved. FNR is located in the cytoplasm and contains a 4Fe4S cluster in the sensory domain. The regulatory concentrations of O-2 are 1-5 mbar. Under these conditions O-2 diffuses to the cytoplasm and is able to react directly with FNR without involvement of other specific enzymes or protein mediators. By oxidation of the FeS cluster, FNR is converted to the inactive state in a reversible process. Reductive activation could be achieved by cellular reductants in the absence of O-2. In addition, O-2 may cause destruction and loss of the FeS cluster, It is not known whether this process is required for regulation of FNR function. (C) 1997 Elsevier Science B.V.
引用
收藏
页码:217 / 234
页数:18
相关论文
共 127 条
[61]   REGULATION OF ANAEROBIC RESPIRATORY PATHWAYS IN WOLINELLA-SUCCINOGENES BY THE PRESENCE OF ELECTRON-ACCEPTORS [J].
LORENZEN, JP ;
KROGER, A ;
UNDEN, G .
ARCHIVES OF MICROBIOLOGY, 1993, 159 (05) :477-483
[62]   Transcriptional control mediated by the ArcA two-component response regulator protein of Escherichia coli: Characterization of DNA binding at target promoters [J].
Lynch, AS ;
Lin, ECC .
JOURNAL OF BACTERIOLOGY, 1996, 178 (21) :6238-6249
[63]   IS ACETYL PHOSPHATE A GLOBAL SIGNAL IN ESCHERICHIA-COLI [J].
MCCLEARY, WR ;
STOCK, JB ;
NINFA, AJ .
JOURNAL OF BACTERIOLOGY, 1993, 175 (10) :2793-2798
[64]  
MEGANATHAN R, 1996, ESCHERICHIA COLI SAL, P642
[65]   Isolation of an oxygen-sensitive FNR protein of Escherichia coli: Interaction at activator and repressor sites of FNR-controlled genes [J].
Melville, SB ;
Gunsalus, RP .
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 1996, 93 (03) :1226-1231
[66]  
MELVILLE SB, 1990, J BIOL CHEM, V265, P18733
[67]   KINETIC-ANALYSIS OF RESPIRATORY NITRATE REDUCTASE FROM ESCHERICHIA-COLI-K12 [J].
MORPETH, FF ;
BOXER, DH .
BIOCHEMISTRY, 1985, 24 (01) :40-46
[68]   IRON CONTENT AND FNR-DEPENDENT GENE-REGULATION IN ESCHERICHIA-COLI [J].
NIEHAUS, F ;
HANTKE, K ;
UNDEN, G .
FEMS MICROBIOLOGY LETTERS, 1991, 84 (03) :319-323
[69]   FIS-DEPENDENT TRANSACTIVATION OF STABLE RNA OPERONS OF ESCHERICHIA-COLI UNDER VARIOUS GROWTH-CONDITIONS [J].
NILSSON, L ;
VERBEEK, H ;
VIJGENBOOM, E ;
VANDRUNEN, C ;
VANET, A ;
BOSCH, L .
JOURNAL OF BACTERIOLOGY, 1992, 174 (03) :921-929
[70]   THE NARK GENE-PRODUCT PARTICIPATES IN NITRATE TRANSPORT INDUCED IN ESCHERICHIA-COLI NITRATE-RESPIRING CELLS [J].
NOJI, S ;
NOHNO, T ;
SAITO, T ;
TANIGUCHI, S .
FEBS LETTERS, 1989, 252 (1-2) :139-143