Biochemical Characterization of the Housekeeping 3-deoxy-D-arabino-heptulosonate-7-phosphate Synthases of Pseudomonas aeruginosa PAO1
Faculty Mentor
Dr. Benjamin Lundgren
Presentation Type
Poster
Start Date
May 2025
End Date
May 2025
Location
PUB NCR
Primary Discipline of Presentation
Chemistry and Biochemistry
Abstract
The opportunistic pathogen Pseudomonas aeruginosa is a frequent cause of life-threatening infections such as pneumonia and sepsis. This bacterium relies on numerous aromatic compounds for its proliferation and virulence, including aromatic toxins (phenazines, pyochelin, quinolines) and aromatic amino acids (tyrosine, phenylalanine, tryptophan). Aromatic compounds are derived from a common precursor called 3-deoxy-D-arabino-heptulosonate-7-phosphate (DAHP), which is synthesized by enzymes known as DAHP synthases. P. aeruginosa PAO1 harbors four DAHP synthases: two housekeeping enzymes (PA1750, PA2943) and two secondary-metabolite enzymes (PhzC1, PhzC2). In this study, we focused on the housekeeping enzymes, which were purified and characterized in vitro. Additionally, the expression profiles and patterns of these enzymes were measured with an enhanced-yellow fluorescent protein reporter. It was found that PA1750 functions as tyrosine-sensitive DAHP synthase, while PA2943 was insensitive or resistant towards all aromatic amino acids. The results of PA1750 are consistent with enzymes of the housekeeping family but not that of PA2943. Moreover, both enzymes were poorly or weakly expressed in P. aeruginosa PAO1 under various growth conditions. In sharp contrast, expression of PhzC1 and PhzC2 – two DAHP synthases associated with phenazine biosynthesis – were significantly expressed in P. aeruginosa PAO1 under all tested conditions. Our findings suggest that PA1750, PhzC1 and PhzC2 are likely involved in housekeeping functions in P. aeruginosa PAO1, while the role of PA2943 remains unclear. Future metabolomic studies and characterization of DAHP synthase activity in cell-extracts are expected to clarify the purpose of each DAHP synthase in the biochemistry and physiology of P. aeruginosa.
Recommended Citation
Wamsley, Ricky; D'Amato, Aidan; and Lundgren, Benjamin PhD, "Biochemical Characterization of the Housekeeping 3-deoxy-D-arabino-heptulosonate-7-phosphate Synthases of Pseudomonas aeruginosa PAO1" (2025). 2025 Symposium. 24.
https://dc.ewu.edu/srcw_2025/ps_2025/p2_2025/24
Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial-No Derivative Works 4.0 International License.
Biochemical Characterization of the Housekeeping 3-deoxy-D-arabino-heptulosonate-7-phosphate Synthases of Pseudomonas aeruginosa PAO1
PUB NCR
The opportunistic pathogen Pseudomonas aeruginosa is a frequent cause of life-threatening infections such as pneumonia and sepsis. This bacterium relies on numerous aromatic compounds for its proliferation and virulence, including aromatic toxins (phenazines, pyochelin, quinolines) and aromatic amino acids (tyrosine, phenylalanine, tryptophan). Aromatic compounds are derived from a common precursor called 3-deoxy-D-arabino-heptulosonate-7-phosphate (DAHP), which is synthesized by enzymes known as DAHP synthases. P. aeruginosa PAO1 harbors four DAHP synthases: two housekeeping enzymes (PA1750, PA2943) and two secondary-metabolite enzymes (PhzC1, PhzC2). In this study, we focused on the housekeeping enzymes, which were purified and characterized in vitro. Additionally, the expression profiles and patterns of these enzymes were measured with an enhanced-yellow fluorescent protein reporter. It was found that PA1750 functions as tyrosine-sensitive DAHP synthase, while PA2943 was insensitive or resistant towards all aromatic amino acids. The results of PA1750 are consistent with enzymes of the housekeeping family but not that of PA2943. Moreover, both enzymes were poorly or weakly expressed in P. aeruginosa PAO1 under various growth conditions. In sharp contrast, expression of PhzC1 and PhzC2 – two DAHP synthases associated with phenazine biosynthesis – were significantly expressed in P. aeruginosa PAO1 under all tested conditions. Our findings suggest that PA1750, PhzC1 and PhzC2 are likely involved in housekeeping functions in P. aeruginosa PAO1, while the role of PA2943 remains unclear. Future metabolomic studies and characterization of DAHP synthase activity in cell-extracts are expected to clarify the purpose of each DAHP synthase in the biochemistry and physiology of P. aeruginosa.
