Assembly principles and structure of a 6.5-MDa bacterial microcompartment shell.

Area of Science:

• Microbiology
• Structural Biology
• Biochemistry

Background:

• Bacteria utilize primitive organelles called bacterial microcompartments.
• These organelles consist of an enzymatic core within a protein shell, sequestering reactions.
• Examples include carboxysomes for carbon dioxide fixation and microcompartments in pathogens.

Purpose of the Study:

• To elucidate the assembly principles of bacterial microcompartment shells.
• To provide structural insights into the intact shell of *Haliangium ochraceum*.
• To inform the design and engineering of novel protein shells.

Main Methods:

• X-ray crystallography of an intact bacterial microcompartment shell.
• Structural analysis of the protein shell components.

Main Results:

• The crystal structure of an intact *Haliangium ochraceum* microcompartment shell was determined.
• This structure reveals fundamental principles governing bacterial microcompartment shell construction.
• The findings highlight conserved features across diverse bacterial microcompartments.

Conclusions:

• The study uncovers the basic principles of bacterial microcompartment shell assembly.
• These principles are conserved across functionally diverse bacterial organelles.
• The findings provide a foundation for engineering new protein shells with tailored functionalities.