Two isoforms of pyruvate kinase enzymes in Pseudomonas aeruginosa with distinct functional and structural properties
type: CreativeWork
description: In most organisms, phosphofructokinase (PFK) and pyruvate kinase (PK) are the key glycolytic regulatory enzymes. However, the opportunistic human pathogen, Pseudomonas aeruginosa, relies entirely on the Entner-Doudoroff pathway for glycolysis, and consequently, does not encode a PFK homologue. It does encode two PK isozymes though, denoted PykA and PykF. This arrangement is uncommon in bacteria, although when it does arise, PykF is usually the dominant isozyme. In this project, I investigated the genetic, functional and structural characteristics of PykA and PykF in P. aeruginosa. The P. aeruginosa PykA and PykF enzymes are phylogenetically distinct, and display a number of unusual properties compared with the isozymes previously characterized from other species. I found that a pykA mutant (but not a pykF mutant) of P. aeruginosa showed decreased growth on glucose and glycerol, suggesting that PykA is the dominant enzyme in this pathogen. However, a mutant defective in both pykA and pykF could be complemented (i.e., made to grow normally on glucose or glycerol) by expression of either enzyme in trans, indicating that both enzymes have the potential to be active. Consistent with the notion that PykA is the dominant enzyme in P. aeruginosa, I also found that PykA (but not PykF) was highly expressed under all conditions tested. Biochemical characterization revealed that purified PykA and PykF share similar catalytic activity, but were differentially regulated by a number of metabolites, most notably by intermediates from the anabolic pentose phosphate pathway. This suggests that P. aeruginosa coordinates glycolysis with the availability of key gluconeogenic precursors, which seems to be a common emerging theme for this pathogen. Given that PykA appears to play an important physiological role, it also represents an excellent target for the development of new antimicrobial agents. With this in mind, I found that a natural product, shikonin, inhibits PykA and prevents gro…
abstract: In most organisms, phosphofructokinase (PFK) and pyruvate kinase (PK) are the key glycolytic regulatory enzymes. However, the opportunistic human pathogen, Pseudomonas aeruginosa, relies entirely on the Entner-Doudoroff pathway for glycolysis, and consequently, does not encode a PFK homologue. It does encode two PK isozymes though, denoted PykA and PykF. This arrangement is uncommon in bacteria, although when it does arise, PykF is usually the dominant isozyme. In this project, I investigated the genetic, functional and structural characteristics of PykA and PykF in P. aeruginosa. The P. aeruginosa PykA and PykF enzymes are phylogenetically distinct, and display a number of unusual properties compared with the isozymes previously characterized from other species. I found that a pykA mutant (but not a pykF mutant) of P. aeruginosa showed decreased growth on glucose and glycerol, suggesting that PykA is the dominant enzyme in this pathogen. However, a mutant defective in both pykA and pykF could be complemented (i.e., made to grow normally on glucose or glycerol) by expression of either enzyme in trans, indicating that both enzymes have the potential to be active. Consistent with the notion that PykA is the dominant enzyme in P. aeruginosa, I also found that PykA (but not PykF) was highly expressed under all conditions tested. Biochemical characterization revealed that purified PykA and PykF share similar catalytic activity, but were differentially regulated by a number of metabolites, most notably by intermediates from the anabolic pentose phosphate pathway. This suggests that P. aeruginosa coordinates glycolysis with the availability of key gluconeogenic precursors, which seems to be a common emerging theme for this pathogen. Given that PykA appears to play an important physiological role, it also represents an excellent target for the development of new antimicrobial agents. With this in mind, I found that a natural product, shikonin, inhibits PykA and prevents gro…
author: Abdelhamid Abdeldayem Karin, Yassmin
language: en
keywords: glycolysis, Pseduomonas, Pseudomonas aeruginosa, pyruvate kinase, PykA, PykF, Entner-Doudoroff pathway, Pentose-Phosphate-pathway, allosteric regulation, structure
license: https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/d50213f8-cc80-4791-ac00-d3e8c51d5ac8/download
license: https://www.rioxx.net/licenses/all-rights-reserved/
date published: 2019-11-30
date modified: 2026-07-22T22:24:06Z
provider: Cambridge University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Cambridge

PropertyValue
property ID: DOI
value: 10.17863/CAM.45135