Recombinant Syntrophus aciditrophicus Lipid A export ATP-binding/permease protein MsbA (msbA)
Description
Overview of MsbA in Gram-Negative Bacteria
MsbA is an essential ATP-binding cassette (ABC) transporter responsible for lipid A and lipopolysaccharide (LPS) transport across the cytoplasmic membrane in Gram-negative bacteria . It functions as a homodimer, with each monomer containing a transmembrane domain (6 helices) and a nucleotide-binding domain (NBD) . MsbA facilitates ATP-dependent flipping of lipid A from the inner to outer leaflet of the membrane, a critical step for outer membrane biogenesis .
Key Features of MsbA:
Substrate Transport Mechanism
-
Lipid A binds MsbA with a of ~0.35–10 μM, while drugs like daunorubicin occupy a separate site .
-
Nucleotide binding (ATP/ADP) modulates lipid A affinity, suggesting bidirectional communication between NBDs and substrate-binding sites .
-
Structural studies reveal an intermediate inward-facing conformation in S. typhimurium MsbA, enabling lipid A entry into the transport pathway .
Enzymatic Activities
-
ATP Hydrolysis: MsbA hydrolyzes ATP to drive lipid flipping, with activity enhanced by lipid A and inhibited by detergents .
-
Adenylate Kinase (AK) Activity: Under ATP-depleted conditions, MsbA catalyzes ADP → ATP + AMP conversion, forming a cyclic ATPase-AK coupling mechanism .
Recombinant MsbA Production
While recombinant S. aciditrophicus MsbA is not explicitly documented, protocols for homologous systems (e.g., P. fluorescens) provide a template:
Expression and Purification (Example from P. fluorescens MsbA ):
| Parameter | Detail |
|---|---|
| Expression Host | E. coli |
| Tag | N-terminal His-tag |
| Protein Length | Full-length (1–601 aa) |
| Purity | >90% (SDS-PAGE) |
| Storage | Lyophilized in Tris/PBS buffer with 6% trehalose (pH 8.0) |
| Reconstitution | Sterile water + 50% glycerol for long-term stability |
Gaps in S. aciditrophicus MsbA Research
Available studies on S. aciditrophicus focus on its acyl-proteome and benzoate degradation pathways , with no direct mention of MsbA. Key findings in this syntroph include:
-
Post-Translational Modifications (PTMs): Heavy lysine acylation (e.g., 3-hydroxypimeloylation) linked to reactive acyl-CoA intermediates .
-
Metabolic Regulation: Functional deacylases suggest dynamic control of acylated enzymes in benzoate degradation .
Future Directions
-
Heterologous Expression: Clone S. aciditrophicus msbA into E. coli or yeast systems, leveraging protocols from P. fluorescens .
-
Functional Assays: Test ATPase activity, lipid A binding, and drug interactions using fluorescence quenching (e.g., MIANS labelling) .
-
Structural Studies: Cryo-EM or X-ray crystallography to resolve substrate-binding sites and conformational changes.
Product Specs
Note: While we prioritize shipping the format currently in stock, we are happy to accommodate specific format requests. Please indicate your preference when placing your order, and we will fulfill it to the best of our ability.
Note: All our proteins are shipped with standard blue ice packs. If you require dry ice shipping, please contact us in advance, as additional fees will apply.
Generally, the shelf life of liquid form is 6 months at -20°C/-80°C. For lyophilized form, the shelf life is 12 months at -20°C/-80°C.
Target Background
KEGG: sat:SYN_01564
STRING: 56780.SYN_01564
