Analysis of hydrogenase 1 levels reveals an intimate link between carbon and hydrogen metabolism in Escherichia coli K-12

TY - JOUR

T1 - Analysis of hydrogenase 1 levels reveals an intimate link between carbon and hydrogen metabolism in Escherichia coli K-12

A1 - Pinske,Constanze

A1 - McDowall,Jennifer S.

A1 - Sargent,Frank

A1 - Sawers,R. Gary

AU - Pinske,Constanze

AU - McDowall,Jennifer S.

AU - Sargent,Frank

AU - Sawers,R. Gary

PY - 2012

Y1 - 2012

N2 - <p>Two of the three [NiFe]-hydrogenases (Hyd) of Escherichia coli have a hydrogen-uptake function in anaerobic metabolism. While Hyd-2 is maximally synthesized when the bacterium grows by fumarate respiration, Hyd-1 synthesis shows a correlation with fermentation of sugar substrates. In an attempt to advance our knowledge on the physiological function of Hyd-1 during fermentative growth, we examined Hyd-1 activity and levels in various derivatives of E. coli K-12 MC4100 with specific defects in sugar utilization. MC4100 lacks a functional fructose phosphotransferase system (PTS) and therefore grows more slowly under anaerobic conditions in rich medium in the presence of D-fructose compared with a-glucose. Growth in the presence of fructose resulted in an approximately 10-fold increase in Hyd-1 levels in comparison with growth under the same conditions with glucose. This increase in the amount of Hyd-1 was not due to regulation at the transcriptional level. Reintroduction of a functional fruBKA-encoded fructose PTS into MC4100 restored growth on D-fructose and reduced Hyd-1 levels to those observed after growth on D-glucose. Reducing the rate of glucose uptake by introducing a mutation in the gene encoding the cAMP receptor protein, or consumption through glycolysis, by introducing a mutation in phosphoglucose isomerase, increased Hyd-1 levels during growth on glucose. These results suggest that the ability to oxidize hydrogen by Hyd-1 shows a strong correlation with the rate of carbon flow through glycolysis and provides a direct link between hydrogen, carbon and energy metabolism.</p>

AB - <p>Two of the three [NiFe]-hydrogenases (Hyd) of Escherichia coli have a hydrogen-uptake function in anaerobic metabolism. While Hyd-2 is maximally synthesized when the bacterium grows by fumarate respiration, Hyd-1 synthesis shows a correlation with fermentation of sugar substrates. In an attempt to advance our knowledge on the physiological function of Hyd-1 during fermentative growth, we examined Hyd-1 activity and levels in various derivatives of E. coli K-12 MC4100 with specific defects in sugar utilization. MC4100 lacks a functional fructose phosphotransferase system (PTS) and therefore grows more slowly under anaerobic conditions in rich medium in the presence of D-fructose compared with a-glucose. Growth in the presence of fructose resulted in an approximately 10-fold increase in Hyd-1 levels in comparison with growth under the same conditions with glucose. This increase in the amount of Hyd-1 was not due to regulation at the transcriptional level. Reintroduction of a functional fruBKA-encoded fructose PTS into MC4100 restored growth on D-fructose and reduced Hyd-1 levels to those observed after growth on D-glucose. Reducing the rate of glucose uptake by introducing a mutation in the gene encoding the cAMP receptor protein, or consumption through glycolysis, by introducing a mutation in phosphoglucose isomerase, increased Hyd-1 levels during growth on glucose. These results suggest that the ability to oxidize hydrogen by Hyd-1 shows a strong correlation with the rate of carbon flow through glycolysis and provides a direct link between hydrogen, carbon and energy metabolism.</p>

U2 - 10.1099/mic.0.056622-0

DO - 10.1099/mic.0.056622-0

M1 - Article

JO - Microbiology-SGM

JF - Microbiology-SGM

SN - 1350-0872

VL - 158

SP - 856

EP - 868

ER -