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Recognition of Actinides by Siderocalin
Ziyi Liu1,2, Qin Wang1, Zhifang Chai2,3
1State Key Laboratory of Fine Chemicals, Liaoning Key Laboratory for Catalytic Conversion of Carbon Resources, School of Chemistry, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, China.
Inorganic Chemistry
|December 29, 2023
Summary
Siderocalin (Scn) exhibits a new recognition mode for actinide-enterobactin (An-Ent) complexes, revealing a seesaw effect between An-Ent binding and Scn recognition. Electrostatic forces, charge, entropy, and adaptability drive high-affinity binding.
Area of Science:
- Biochemistry
- Computational Chemistry
- Biophysical Chemistry
Background:
- Siderocalins (Scn) are crucial for sequestering iron, but their interactions with other metal complexes are less understood.
- Actinides (An) pose unique binding challenges due to their diverse chemistry.
- Enterobactin (Ent) is a high-affinity siderophore for iron.
Purpose of the Study:
- To elucidate the molecular recognition mechanism of siderocalin (Scn) for actinide-enterobactin (An-Ent) complexes.
- To investigate the interplay between actinide affinity for enterobactin and Scn recognition.
- To identify key factors governing the binding affinity and specificity.
Main Methods:
- Plain simulations and enhanced sampling techniques were employed.
- Computational modeling was used to analyze molecular interactions.
- Binding affinities and recognition modes were investigated.
Main Results:
- A novel siderocalin (Scn) recognition mode for An-Ent complexes was discovered.
- A "seesaw" relationship was identified: increased actinide affinity to Ent correlates with decreased Scn recognition.
- Electrostatic interactions were found to be the dominant force in competitive binding.
- Hydrolysis-induced negative charge, water expulsion-driven entropy, and Ent's conformational flexibility enhance high-affinity recognition.
Conclusions:
- Siderocalin exhibits a unique, adaptable recognition strategy for An-Ent complexes.
- The binding mechanism is governed by a balance of electrostatic, entropic, and conformational factors.
- This study provides fundamental insights into the biophysical chemistry of actinide complex recognition.
