Alfia Fitrianita, Naufal Abiyyu, Berry Juliandi, Akhmad Sabarudin, Tri Rini Nuringtyas, Hendra Gunosewoyo, Syahputra Wibowo, Rony Abdi Syahputra
The authors regret that there is an editorial error. In the RIN discussion, Fig. 8 and 9 have been revised to correct their previous misplacement. Revisions have also been made to the Source of Funding and Acknowledgment sections to ensure accuracy. The authors would like to apologise for any inconvenience caused. Residue Interaction Network (RIN) analysis.(Figure presented) Fig. 8. Residue Interaction Network (RIN) analysis of native and glycated human serum albumin (HSA and gHSA) under different ligand-binding conditions, generated using RINmaker. A. HSA; b. gHSA; c. HSA and ASX; d. gHSA and ASX; e. HSA and ASXZn2+ (1:2); f. gHSA and ASXZn2+ (1:2); g. HSA and ASXZn2+ (3:1); h. gHSA and ASXZn2+ (3:1).(Figure presented) Fig. 9. Distribution of interaction types across different protein-ligand systems involving HSA and gHSA with ASX and ASXZn2+ complexes. The stacked bar chart displays the frequency of various interaction types, including hydrogen bonds (HBOND), hydrophobic contacts, ionic interactions, π-π stacking, and van der Waals (VDW) interactions. These interactions are further categorized based on main chain-main chain (MC_MC), main chain-side chain (MC_SC), side chain-main chain (SC_MC), and side chain-side chain (SC_SC) contacts. Notably, VDW:SC_SC interactions dominate across all conditions. Systems involving ASXZn2+ (1:2) show higher total interaction counts, especially in gHSA, indicating enhanced structural stabilization potentially due to increased intermolecular contact diversity and frequency. The RIN analysis illustrated in Figs. 8 and 9 provides a comparative overview of how native and glycated human serum albumin (HSA and gHSA) interact with astaxanthin (ASX) and its Zn2+ complexes. The findings highlight structural and interactional differences across various ligand-binding conditions. The baseline visual network complexity and ligand influence (Fig. 8) comparison between native and gHSA (A and B) shows that glycated HSA (gHSA) exhibits altered residue interaction networks relative to native HSA. This suggests that glycation disrupts or modifies intra-protein residue communication, likely due to structural changes caused by glycation-induced crosslinking or modification of lysine/arginine residues. Glycation induces significant structural alterations, primarily through the modification of lysine and arginine residues, which affect the network of residue interactions within the protein (Qiu et al., 2021). The introduction of ASX alone leads to denser interaction networks (C, D), suggesting stabilizing interactions. The effect is more pronounced in gHSA, indicating ASX may partially compensate for glycation-induced structural destabilization. The ASXZn2+ complexes, particularly at 1:2 stoichiometry (E, F), yield significantly denser and more interconnected RINs, especially in gHSA. This implies a stronger stabilizing effect through metal coordination, which enhances residue-residue interactions. At 3:1 stoichiometry (G, H), a noticeable shift occurs. In native HSA, excess ASX might lead to competitive binding or steric hindrance, slightly reducing network compactness. Astaxanthin is known to form a more stable interaction network, including hydrogen bonds and π-π stacking, particularly with aromatic residues in HSA and gHSA, as revealed by interaction mapping using RINmaker (Wibowo et al., 2022). Conversely, gHSA maintains or increases network complexity, possibly due to different binding pocket availability or altered conformational flexibility. Van der Waals Interactions (Fig. 9) dominate across all conditions, reaffirming their importance in maintaining tertiary structure and mediating non-covalent interactions in HSA-ligand complexes. Their prevalence in both native and glycated forms suggests a conserved role despite glycation. Systems with ASXZn2+ at 1:2 ratio exhibit the highest total number of interactions, particularly in gHSA. This implies that Zn2+ coordination contributes to a richer and more diverse interaction profile, potentially restoring structural rigidity compromised by glycation. The increase in hydrogen bonds, ionic, and π-π stacking interactions in ASXZn2+ complexes enhances the thermodynamic and kinetic stability of the complex. This suggests a promising avenue for counteracting glycation effects via antioxidant-metal ions complex intervention. Glycation alters native protein residue connectivity, likely impairing function. ASX and especially ASXZn2+ complexes can reinforce or restore interaction networks. The 1:2 ASXZn2+ complex emerges as the most structurally stabilizing, especially in glycated HSA. These findings support the hypothesis that metal-carotenoid complexes like ASXZn2+ could serve as stabilizing agents in glycation-compromised proteins, with potential implications in anti-glycation therapies or drug delivery systems. The ASXZn2+ complex HSA been proposed as a potential candidate for anti-glycation therapy due to its ability to enhance compactness, reduce excessive flexibility, and restore interaction networks disrupted by AGEs (Wibowo et al., 2022). DECLARATIONS. SOURCE OF FUNDING. RIIM Kolaborasi Internasional LPDP - KONEKSI. © 2026 The Author.
Biotechnology study program, Postgraduate School, IPB University, Dramaga Campus, Bogor, 16680, Indonesia; Department of Biochemistry, Faculty of Mathematics and Natural Sciences, IPB University, Dramaga Campus, Bogor, 16680, Indonesia; Department of Biology, Faculty of Mathematics and Natural Sciences, IPB University, Dramaga Campus, Bogor, 16680, Indonesia; Department of Chemistry, Faculty of Mathematics and Natural Sciences, Brawijaya University, Malang, 65145, Indonesia; Faculty of Biology, Universitas Gadjah Mada, Jalan Teknika Selatan, Sekip Utara, Yogyakarta, 55281, Indonesia; Curtin Medical School, Faculty of Health Sciences, Curtin University, Bentley, Perth, 6102, WA, Australia; Eijkman Research Center for Molecular Biology, National Research and Innovation Agency (BRIN), Cibinong, Bogor, 16911, Indonesia; Department of Pharmacology, Faculty of Pharmacy, Universitas Sumatera Utara, Medan, Indonesia
