Molecular Dynamics Simulations of Biotin in Aqueous Solution

Area of Science:

• Biochemistry
• Computational Chemistry
• Molecular Biophysics

Background:

• Biotin is a vital coenzyme involved in numerous carboxylation reactions.
• Understanding biotin's conformational dynamics in solution is crucial for elucidating its biological functions.
• Previous studies have not fully explored biotin's behavior in explicit aqueous environments.

Purpose of the Study:

• To investigate the conformational properties and dynamics of biotin in explicit water using molecular dynamics (MD) simulations.
• To characterize the different states biotin adopts in solution and identify stabilizing interactions.
• To explore the potential role of these dynamics in the activation of biotin's reactive sites.

Main Methods:

• Utilized three independent molecular dynamics simulations of biotin in explicit water.
• Analyzed simulation trajectories using metrics such as intramolecular distance, radius of gyration, root-mean-square deviation, and solvent-accessible surface area.
• Examined hydrogen bonding patterns, including intramolecular and water-mediated interactions.

Main Results:

• Biotin exhibits significant flexibility in aqueous solution, transitioning between extended, semifolded, and folded conformations.
• Folded states are stabilized by intramolecular hydrogen bonds.
• Semifolded states involve water-mediated hydrogen bonds between the ureido and carboxyl groups.
• Hydrogen bonding cooperativity in folded/semifolded states likely activates the 1-NH site.

Conclusions:

• Biotin's conformational flexibility in water is a key characteristic.
• Intramolecular and water-mediated hydrogen bonds play a significant role in stabilizing biotin's conformations.
• Hydrogen bonding cooperativity is proposed to be essential for activating the 1-NH site, facilitating its role in enzymatic reactions.