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The E. coli BtuCD structure: a framework for ABC transporter architecture and mechanism
Kaspar P Locher1, Allen T Lee, Douglas C Rees
1Howard Hughes Medical Institute and Division of Chemistry and Chemical Engineering, Mail Code 147-75CH, California Institute of Technology, Pasadena, CA 91125, USA. locher@caltech.edu
Science (New York, N.Y.)
|May 11, 2002
Summary
Researchers determined the crystal structure of the Escherichia coli BtuCD protein, an ABC transporter crucial for vitamin B12 uptake. This structure reveals unique arrangements of its subunits, offering insights into transporter mechanisms.
Area of Science:
- Biochemistry
- Structural Biology
- Molecular Biology
Background:
- ATP-binding cassette (ABC) transporters are vital membrane proteins.
- They utilize adenosine triphosphate (ATP) hydrolysis for substrate translocation.
- Dysfunction is linked to diseases like cystic fibrosis and multidrug resistance.
Purpose of the Study:
- To elucidate the structural basis of vitamin B12 uptake.
- To characterize the structure of the Escherichia coli BtuCD protein.
Main Methods:
- X-ray crystallography
- High-resolution structural determination (3.2 angstroms)
- Analysis of protein subunit arrangement and interactions
Main Results:
- The crystal structure of E. coli BtuCD was determined.
- Distinct arrangements of ATP-binding cassettes (BtuD) and membrane-spanning subunits (BtuC) were observed.
- A unique translocation pathway and gate region within BtuC were identified.
Conclusions:
- The BtuCD structure provides a detailed molecular model for ABC transporter function.
- The findings highlight conserved structural motifs potentially relevant to other ABC transporters.
- This work advances understanding of nutrient uptake mechanisms in bacteria.
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