Exploring the Extreme Acid Tolerance of a Dynamic Protein Nanocage.
Biomacromolecules
; 24(3): 1388-1399, 2023 03 13.
Article
em En
| MEDLINE
| ID: mdl-36796007
ABSTRACT
Encapsulins are microbial protein nanocages capable of efficient self-assembly and cargo enzyme encapsulation. Due to their favorable properties, including high thermostability, protease resistance, and robust heterologous expression, encapsulins have become popular bioengineering tools for applications in medicine, catalysis, and nanotechnology. Resistance against physicochemical extremes like high temperature and low pH is a highly desirable feature for many biotechnological applications. However, no systematic search for acid-stable encapsulins has been carried out, while the influence of pH on encapsulin shells has so far not been thoroughly explored. Here, we report on a newly identified encapsulin nanocage from the acid-tolerant bacterium Acidipropionibacterium acidipropionici. Using transmission electron microscopy, dynamic light scattering, and proteolytic assays, we demonstrate its extreme acid tolerance and resilience against proteases. We structurally characterize the novel nanocage using cryo-electron microscopy, revealing a dynamic five-fold pore that displays distinct "closed" and "open" states at neutral pH but only a singular "closed" state under strongly acidic conditions. Further, the "open" state exhibits the largest pore in an encapsulin shell reported to date. Non-native protein encapsulation capabilities are demonstrated, and the influence of external pH on internalized cargo is explored. Our results expand the biotechnological application range of encapsulin nanocages toward potential uses under strongly acidic conditions and highlight pH-responsive encapsulin pore dynamics.
Texto completo:
1
Bases de dados:
MEDLINE
Assunto principal:
Bactérias
/
Proteínas de Bactérias
Idioma:
En
Revista:
Biomacromolecules
Assunto da revista:
BIOLOGIA MOLECULAR
Ano de publicação:
2023
Tipo de documento:
Article
País de afiliação:
Estados Unidos