Recombinant Staphylococcus aureus 4,4'-diaponeurosporenoate glycosyltransferase (crtQ)
Description
Introduction to Recombinant Staphylococcus aureus 4,4'-Diaponeurosporenoate Glycosyltransferase (crtQ)
The recombinant enzyme 4,4'-diaponeurosporenoate glycosyltransferase (crtQ) is a glycosyltransferase (GT) encoded by the crtQ gene in Staphylococcus aureus. It plays a critical role in the biosynthesis of staphyloxanthin, a C30 carotenoid pigment responsible for the golden coloration of S. aureus and its resistance to oxidative stress and host immune responses . Recombinant crtQ refers to the heterologously expressed version of this enzyme, often used in biochemical studies to dissect its catalytic mechanism and functional roles.
Biochemical Function and Catalytic Mechanism
crtQ belongs to the glycosyltransferase family A (GT-A) and catalyzes the esterification of glucose at the C1'' position of 4,4'-diaponeurosporenic acid, forming glycosyl-4,4'-diaponeurosporenoate . This reaction is a pivotal step in staphyloxanthin biosynthesis, bridging the oxidative modification of carotenoid intermediates and their subsequent acylation.
Key Reaction:
| Parameter | Value/Description |
|---|---|
| EC Number | 2.4.1.- (Hexosyltransferases) |
| Substrates | 4,4'-diaponeurosporenic acid, Glucose |
| Product | Glycosyl-4,4'-diaponeurosporenoate |
| Gene | crtQ (Encoded in crtOPQMN operon) |
Role in Staphyloxanthin Biosynthesis
Staphyloxanthin biosynthesis involves a six-enzyme pathway:
Functional Studies in E. coli
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Pathway Reconstitution: Heterologous expression of crtOPQMN in E. coli yields glycosyl-4,4'-diaponeurosporenoate as a major product, confirming crtQ’s role .
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Intermediate Accumulation: Deletion of crtQ leads to accumulation of 4,4'-diaponeurosporen-4-al, highlighting its necessity for downstream acylation .
Drug Target Potential
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Inhibitor Screening: CrtM (early pathway enzyme) is targeted by cholesterol biosynthesis inhibitors, underscoring the pathway’s vulnerability .
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Vaccine Development: Staphyloxanthin’s role in virulence makes crtQ a candidate for anti-infective therapies .
Table 1: Enzyme Characteristics
| Property | Detail |
|---|---|
| UniProt ID | Q2FV58 |
| Gene Locus | SAOUHSC_02880 |
| Taxonomy | Staphylococcus aureus subsp. aureus |
| Catalytic Activity | Glucose esterification at C1'' position |
Table 2: Staphyloxanthin Biosynthetic Pathway
| Enzyme | Substrate | Product |
|---|---|---|
| CrtM | Farnesyl diphosphate | Dehydrosqualene |
| CrtN | Dehydrosqualene | 4,4'-Diaponeurosporene |
| CrtP | 4,4'-Diaponeurosporene | 4,4'-Diaponeurosporenic acid |
| crtQ | 4,4'-Diaponeurosporenic acid | Glycosyl-4,4'-diaponeurosporenoate |
| CrtO | Glycosyl-4,4'-diaponeurosporenoate | Staphyloxanthin |
Product Specs
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Generally, the shelf life of liquid forms is 6 months at -20°C/-80°C. Lyophilized forms have a shelf life of 12 months at -20°C/-80°C.
Target Background
KEGG: sao:SAOUHSC_02880
STRING: 93061.SAOUHSC_02880
