Xylan adsorption on cellulose: Preferred alignment and local surface immobilizing effect.

Area of Science:

• Plant biology
• Biochemistry
• Materials science

Background:

• Xylan and cellulose microfibrils are crucial for secondary cell wall integrity.
• The precise mechanisms of their assembly and impact on cellulose surface polymers remain unclear.

Purpose of the Study:

• To investigate xylan adsorption onto hydrated cellulose fibrils using molecular dynamics simulations.
• To elucidate the structural and dynamic consequences of xylan-cellulose interactions.

Main Methods:

• Utilized molecular dynamics simulations to model xylan adsorption on cellulose fibrils.
• Analyzed hydrogen bonding patterns and dynamics of cellulose surface residues.

Main Results:

• Demonstrated that an antiparallel orientation of xylan on cellulose is thermodynamically preferred.
• Observed orientation-dependent hydrogen bond formation and restricted dynamics of adjacent glucose residues.
• Reported a three-fold increase in 13C NMR T1 relaxation time for surface glucose residues due to xylan adsorption.

Conclusions:

• Xylan forms a rigid, ordered layer around cellulose fibrils.
• This layer acts as a transition phase between cellulose and more disordered domains.
• Findings provide a molecular-level understanding of xylan-cellulose interactions in plant cell walls.