Modular hyperthermostable bacterial endo-β-1,4-mannanase: molecular shape, flexibility and temperature-dependent...

Area of Science:

• Enzymology
• Structural Biology
• Biophysics

Background:

• Endo-β-1,4-mannanase (TpMan) from Thermotoga petrophila is a hyperthermostable enzyme.
• TpMan consists of a GH5 catalytic domain linked to a carbohydrate-binding domain.
• The three-dimensional structure and domain arrangement of TpMan remain uncharacterized.

Purpose of the Study:

• To determine the first structural characterization of the entire TpMan enzyme.
• To investigate the low-resolution model, dimensions, and flexibility of TpMan.
• To understand the role of the linker in domain spatial arrangement at varying temperatures.

Main Methods:

• Small-angle X-ray scattering (SAXS) was employed for structural characterization.
• Three-dimensional structures of individual domains were utilized.
• Rigid-body modeling was performed to describe preferred conformations.

Main Results:

• The linker region of TpMan is compact and occupies a small volume.
• TpMan exhibits molecular flexibility in solution at 20°C.
• A temperature-driven conformational transition occurs without significant secondary structure disruption.

Conclusions:

• The linker optimizes domain geometry for substrate interaction at high temperatures.
• TpMan possesses a preferred conformation despite solution flexibility.
• These findings provide a basis for future biophysical studies of TpMan.