Pyruvate Formate Lyase and Acetate Kinase Are Essential for Anaerobic Growth ofEscherichia colion Xylose

• DOI: 10.1128/jb.186.22.7593-7600.2004
• Publication Date: 2004-10-31T07:42:41Z
• Authors: Adnan Hasona; Youngnyun Kim; F. G. Healy; L. O. Ingram; K. T. Shanmugam
• Keywords: Xylose metabolism; Acetate kinase; ATP citrate lyase; Mixed acid fermentation; Pentose

During anaerobic growth of bacteria, organic intermediates metabolism, such as pyruvate or its derivatives, serve electron acceptors to maintain the overall redox balance. Under these conditions, ATP needed for cell is derived from substrate-level phosphorylation. In Escherichia coli, conversion glucose yields 2 net ATPs, while metabolism a pentose, xylose, only 0.67 per xylose due need one (each) transport and xylulose fermentative growth, E. coli produces equimolar amounts acetate ethanol two pyruvates, reactions generate additional pyruvates (one hexose equivalent) still maintaining Conversion increases yield 1.5 xylose. An pfl mutant lacking formate lyase cannot convert acetyl coenzyme A, required precursor production, could not produce this ATP. mutants failed grow under conditions in minimal medium without any negative effect on their survival aerobic growth. ackA mutant, ability phosphate, also confirming produced by kinase Since arabinose AraE, low-affinity, high-capacity, arabinose/H+ symport, conserves expended pentose ABC transporter, both grew anaerobically with arabinose. AraE-based transport, achieved after constitutively expressing araE, supported medium. These results suggest that enough provide maintenance energy but support Thus, are essential energetic constraints.