Recombinant Plasmodium vivax Alpha-tubulin N-acetyltransferase (PVX_099660)
Description
Functional Role and Mechanism
Alpha-tubulin N-acetyltransferases (ATATs) are critical for microtubule dynamics, influencing processes like cell division, intracellular transport, and pathogen motility. PVX_099660 is predicted to:
-
Acetylate α-tubulin at K40, stabilizing microtubules by reducing their mechanical rigidity .
-
Participate in Plasmodium cytoskeletal regulation, potentially affecting parasite motility (e.g., glideosome function in malaria parasites) .
-
Exhibit autoacetylation activity, a regulatory feature observed in TcATAT and human ATAT1 .
Enzymatic Activity
Based on homologs, PVX_099660 is expected to:
-
Prefer polymerized tubulin (microtubules) over free αβ-tubulin dimers, with a higher k<sub>cat</sub> for microtubules .
-
Require AcCoA as a cofactor, with kinetic parameters comparable to human ATAT1 (Km ≈ 2–3 μM for AcCoA) .
-
Display temperature-dependent activity, peaking at 37°C for optimal parasite growth .
Inferred Kinetic Parameters
| Substrate | k<sub>cat</sub> (h⁻¹) | K<sub>m</sub> (μM) |
|---|---|---|
| Free αβ-tubulin | 0.3–0.5 | 2.0 |
| Polymerized microtubules | 2.0–2.5 | 1.6 |
| Acetyl-CoA | 1.4–1.6 | 2.2 |
Biological Implications in Plasmodium
-
Drug Resistance: Hyperacetylation via ATAT overexpression in T. cruzi increases resistance to microtubule-targeting drugs (e.g., oryzalin) . PVX_099660 may similarly confer resistance to antimalarials like dinitroanilines.
-
Cell Cycle Defects: Overexpression of TcATAT disrupts kinetoplast division and mitochondrial structure . In Plasmodium, dysregulated PVX_099660 activity could impair apicoplast segregation or merozoite invasion.
-
Motility and Invasion: Acetylated microtubules in Plasmodium gametocytes or sporozoites may enhance mechanical resilience, aiding host-cell traversal .
Research Gaps and Future Directions
-
Direct Characterization: No structural or kinetic data for PVX_099660 are publicly available. Recombinant protein production and crystallography studies are needed.
-
Functional Studies: Knockout/overexpression experiments in Plasmodium could clarify its role in microtubule dynamics and parasite viability.
-
Therapeutic Potential: ATAT inhibitors (e.g., small molecules targeting the AcCoA-binding site) might disrupt Plasmodium microtubules, offering novel antimalarial strategies .
Product Specs
Target Background
KEGG: pvx:PVX_099660
