BTubuli

BTubuli are a class of tubular cytoskeletal filaments described in synthetic biology experiments and theoretical models as tubulin-like polymers that organize the internal architecture of engineered cells and cell-free systems. They are built from BTubulin subunits that assemble into linear protofilaments, which laterally associate to form a hollow, cylindrical filament. The architecture is reminiscent of microtubules but is based on a distinct family of tubulin-like proteins. Diameters are on the order of tens of nanometers, with lengths ranging from hundreds of nanometers to several micrometers depending on conditions.

Biogenesis and dynamics: BTubulin binds guanine nucleotides and hydrolysis drives dynamic behavior akin to polymerization and depolymerization, though regulation differs from canonical microtubules. Assembly is aided by BTubulin-binding factors and cross-linking proteins that stabilize bundles or networks. The exact regulatory mechanisms can vary between experimental systems and synthetic contexts.

Function and applications: In synthetic cells and reconstituted systems, BTubuli provide mechanical support, help organize spatial patterns of enzymes, and act as tracks for engineered motor-like devices. They can template nanomaterial deposition and serve as scaffolds for division-like processes in minimal cell models. Their modularity makes them attractive for studying cytoskeletal principles and for constructing nanobiotechnological tools.

Discovery and status: The term BTubuli was introduced in early 21st-century literature to describe these tubule-like polymers of BTubulin. As a topic of ongoing research, natural occurrence remains unconfirmed, and properties vary with sequence, environment, and accessory proteins.

See also: Microtubules, Tubulin, Cytoskeleton, Synthetic biology.