Abstract: Background: Present world is badly affected by AIDS. The chief causative agent for AIDS
is HIV. The essential milk proteins; bovine lactoferrin (bLF) and human lactoferrin (hLF) are known
to obstruct the interaction between HIV gp120 and DC-SIGN protein after sexual transmission. Earlier
several research studies have been performed to document the active participation of gp120 protein
and lactoferrins, but the molecular-level analysis for lactoferrins (bLF and hLF) and gp120 interaction
was never explored.
Methodology: Firstly, three essential proteins (hLF, bLF and gp120) were analyzed and demonstrated
for their experimentally validated x-ray crystallographic structures. The bLF-gp120 and hLF-gp120
protein complexes were formed. After energy minimization and simulation, the residual participation
was observed. Additionally, thermodynamic properties and stability of the proteins were evaluated for
the individual complexes.
Results, Discussion and Conclusion: Residual interactions showed the predominant ionic-ionic interactions
to be double for bLF-gp120 complex than hLF-gp120 complex. 4 ionic-ionic interactions by
Glu residues from bLF protein were strong enough to accommodate gp120 protein into the pocket
formed in bLF protein. Net area for solvent accessibility and electrostatic surface potential were observed
to satisfy better interaction with bLF. Fascinatingly, increased percentage of β-sheets in gp120
after interacting with bLF depicted that gp120 adopted a steadier conformation, whereas; upon interaction
with hLF, flexibility of gp120 got increased with increased percentage of residues forming
coils. From ΔG evaluations, hLF protein was observed to interact less spontaneously with gp120 protein
than bLF protein, thereby allowing the flexibility in the gp120 protein to interact with other host
cells in human. Altogether, it affirms gp120 to have weaker interaction with hLF. Therefore, bLF acts
as a stronger proficient HIV inhibitor. Thus, this probe provides a coherent outlook for investigating
into the mutational impacts on bLF and hLF protein and further interaction with gp120.