Effect of maleylation and denaturation of human serum albumin on its interaction with scavenger receptors.

The specific recognition of serum proteins by scavenger receptors is critical and fundamental in many biological processes. However, the underlying mechanism of scavenger receptor-serum protein interaction remains elusive. In this work, taking scavenger receptors class A1 (SR-A1) as an example, we systematically investigate its interaction with human serum albumin (HSA) at different states through a combination of molecular docking and all-atom molecular dynamics simulations. It is found that native HSA can moderately bind to collagen-like (CL) region or scavenger receptor cysteine-rich (SRCR) region, with both electrostatic (ELE) and van der Waals (VDW) interactions, playing important roles. After maleylation, the binding energy, particularly the ELE energy, between HSA and CL region is significantly enhanced, while the binding energy between HSA and SRCR region remains nearly unchanged. Additionally, we also observe that unfolding of the secondary structures in HSA leads to a larger contact surface area between denatured HSA and CL region, but has little impact on the HSA-SRCR region interaction. Therefore, similar to maleylated HSA, denatured HSA is also more likely to bind to the CL region of SR-A1.