Related Experiment Video
Updated: Aug 3, 2026
12:42
Microfluidic Mixers for Studying Protein Folding
Published on: April 10, 2012
Protein folding and maturation in a cell-free system
D N Hebert1, J X Zhang, A Helenius
1Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst 01003, USA. dhebert@biochem.umass.edu
Summary
This study demonstrates a cell-free system for tracking influenza hemagglutinin maturation. The system effectively models protein oxidation, oligomerization, and chaperone interactions during secretory pathway transit.
Area of Science:
- Biochemistry
- Molecular Biology
- Virology
Background:
- Reduced cellular systems offer valuable tools for studying complex biological processes.
- Influenza hemagglutinin (HA) is a viral glycoprotein crucial for understanding host-pathogen interactions and protein maturation.
Purpose of the Study:
- To characterize the oxidation, oligomerization, and chaperone binding of influenza hemagglutinin in a cell-free system.
- To establish a functional cell-free model for studying proteins within the secretory pathway.
Main Methods:
- Utilized a cell-free system comprising rough endoplasmic reticulum microsomes and reticulocyte lysate.
- Investigated hemagglutinin maturation, including disulfide bond formation and oligomerization.
- Assessed temporal interactions with molecular chaperones calnexin and calreticulin.
- Developed a method for protein translocation into lumenal-depleted microsomes.
Main Results:
- The cell-free system supported complete hemagglutinin maturation from early oxidative intermediates to mature homo-oligomers.
- Disulfide bond formation and oligomerization exhibited time- and temperature-dependent kinetics.
- Hemagglutinin's association with calnexin and calreticulin mirrored in-cell observations with nascent chains.
- Successful protein translocation into microsomes was achieved.
Conclusions:
- The described cell-free system effectively recapitulates key aspects of influenza hemagglutinin maturation.
- This system provides a powerful tool for dissecting the biological maturation of secretory pathway proteins.
- It facilitates detailed studies of protein folding, disulfide bond formation, and chaperone interactions in vitro.
Related Concept Videos
01:22Protein Folding
Overview
01:22Protein Folding
Overview
03:00Molecular Chaperones and Protein Folding
The native conformation of a protein is formed by interactions between the side chains of its constituent amino acids. When the amino acids cannot form these interactions, the protein cannot fold by itself and needs chaperones. Notably, chaperones do not relay any additional information required for the folding of polypeptides; the native conformation of a protein is determined solely by its amino acid sequence. Chaperones catalyze protein folding without being a part of the folded protein.
The...
The...
01:25Protein Folding
Proteins are chains of amino acids linked together by peptide bonds. Upon synthesis, a protein folds into a three-dimensional conformation, critical to its biological function. Interactions between its constituent amino acids guide protein folding, and hence the protein structure is primarily dependent on its amino acid sequence.
Protein Structure Is Critical to Its Biological Function
Proteins perform a wide range of biological functions such as catalyzing chemical reactions, providing...
Protein Structure Is Critical to Its Biological Function
Proteins perform a wide range of biological functions such as catalyzing chemical reactions, providing...
03:00Molecular Chaperones and Protein Folding
The native conformation of a protein is formed by interactions between the side chains of its constituent amino acids. When the amino acids cannot form these interactions, the protein cannot fold by itself and needs chaperones. Notably, chaperones do not relay any additional information required for the folding of polypeptides; the native conformation of a protein is determined solely by its amino acid sequence. Chaperones catalyze protein folding without being a part of the folded protein.
The...
The...
01:26Bacterial Protein Maturation
Bacterial protein maturation is a tightly regulated process that ensures newly synthesized polypeptides achieve correct functional conformations. This maturation involves a series of modifications, folding events, and quality control steps, often assisted by specialized chaperone proteins.N-Terminal ModificationsThe maturation of bacterial polypeptides begins cotranslationally as the polypeptide exits the ribosome. The first amino acid, N-formylmethionine (fMet), is typically modified at the...