https://doi.org/10.1021/acsnano.5c02235
요약
- 염다리 상호작용에 의한 공응집체(coacervate)의 소포(vesicle) 전환 발견: Arginine-rich polypeptide인 PolyR와 phosphate-rich polymer인 PolyP 간의 guanidinium-phosphate salt-bridge 상호작용에 의해, 액체 상태의 coacervate가 안정적인 vesicle로 전환됨을 규명함.
- 전환 현상은 음전하 물질 종류와 무관하게 발생: 초기 anionic counterpart가 ATP이든 NADPH이든 상관없이 소포 전환이 일어났으며, 이는 단순 정전기적 인력보다는 salt-bridge가 주도적임을 의미.
- 구아니디늄기(guanidinium group)의 특수성 확인: lysine 등 다른 양이온 아미노산과 달리, arginine의 guanidinium기는 sp² hybrid화된 quasi-aromatic 구조 덕분에 π-π stack 및 hydrogen bonding 등 복합적인 상호작용이 가능, 특히 salt-bridge 효과가 큼.
- 구조적 안정성과 조절 가능성 확보: 생성된 vesicle은 넓은 pH(4.0–12.0), 온도(4–80°C), 이온 농도에서도 안정하며, 다양한 염 종류(Hofmeister series)를 바탕으로 transformation 효율 조절 가능함.
- 인공 조직(tissue-like structure)으로 응용 가능성 입증: 두 종류의 PRV (ATP 기반, NADPH 기반)를 DEAE-DEX를 통해 응집시켜 이질적인 인공 조직 형성에 성공, cascade enzymatic reaction에서도 속도 향상을 유도함.
Abstract
Polypeptide-based liquid–liquid phase separation (LLPS) has received considerable attention as it governs the formation of membraneless organelles in cells. However, the detailed mechanistic understanding of how one of the most prevalent cationic amino acids in proteins, arginine, interacts with various biomolecules to induce phase separation and undergo morphogenesis remains to be resolved. Herein, we report the phase separation behavior and transformation of arginine-rich coacervates into vesicular structures upon introducing polyphosphates. Transformation into vesicles was shown to occur independent of the initial anionic counterparts and was driven by salt-bridge interactions between guanidinium groups of arginine residues and phosphates. We also investigate the role of intermolecular forces and ionic effects on the morphological transformation and further exploit their potential in the assembly of artificial tissue-like constructs. Overall, our findings underpin a unifying principle for vesicle transformation from arginine-rich coacervates and their potency for reconstituting hierarchical biological microcompartments.