Recombinant Burkholderia phymatum GMP synthase [glutamine-hydrolyzing] (guaA), partial
Description
Biochemical Role of GuaA in Purine Biosynthesis
GMP synthase (GuaA) is a class I glutamine amidotransferase (GATase) that operates in two catalytic steps:
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Glutaminase activity: Hydrolysis of glutamine to generate ammonia .
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ATPPase activity: Formation of an adenyl-XMP intermediate, followed by nucleophilic substitution to yield GMP .
In Burkholderia phymatum, GuaA is essential for nucleotide biosynthesis, particularly under conditions where exogenous guanine is unavailable . The enzyme’s activity is tightly regulated by substrate availability and structural dynamics, including domain rotations that coordinate ammonia channeling between active sites .
Recombinant Production and Characterization
The partial recombinant GuaA from B. phymatum is produced in heterologous expression systems (e.g., E. coli) for research applications. Key features include:
Research Applications and Findings
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Drug Target Potential: GuaA is essential in pathogens like Acinetobacter baumannii and Clostridioides difficile, making it a target for antimicrobial development .
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Auxotrophy Studies: guaA mutants require exogenous GMP or guanine for survival, highlighting its role in de novo purine synthesis .
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Symbiotic Relevance: In rhizobia like B. phymatum, purine metabolism influences nitrogen fixation efficiency, though direct evidence linking GuaA to symbiosis remains underexplored .
Table 2: GuaA Homologs in Burkholderia Species57
| Species | UniProt ID | Sequence Identity | Key Differences |
|---|---|---|---|
| B. phymatum | B2JIA0 | 100% | Unique residues in GATase domain |
| B. phytofirmans | B2T5G8 | 92% | Variant ATPPase binding motifs |
Challenges and Future Directions
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Structural Dynamics: The partial recombinant form lacks full-length functional domains, limiting mechanistic studies .
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Therapeutic Exploration: High conservation of GuaA across bacteria supports broad-spectrum inhibitor development, though species-specific variations (e.g., water network stability in A. baumannii) require tailored approaches .
Product Specs
Target Background
KEGG: bph:Bphy_1312
STRING: 391038.Bphy_1312
