ABC transporters: bacterial exporters

Area of Science:

• Biochemistry
• Molecular Biology
• Microbiology

Background:

• ATP-binding cassette (ABC) transporters are a large superfamily of proteins characterized by a common ATP-binding domain.
• They are crucial for transporting various molecules across cellular membranes.
• ABC transporters are broadly classified into bacterial importers, eukaryotic transporters, and bacterial exporters.

Purpose of the Study:

• To provide a comprehensive review of bacterial ABC exporters.
• To functionally subdivide bacterial ABC exporter systems based on translocated substrates.
• To illustrate the current understanding of this protein family using prototype exporters.

Main Methods:

• Functional classification of bacterial ABC exporters into protein, peptide, and non-protein substrate transporters.
• Detailed description of prototype exporter systems from various bacterial species.
• Phylogenetic analysis of ATP-binding domains from 29 bacterial ABC exporters.

Main Results:

• The review covers over 40 bacterial ABC exporter systems.
• Bacterial ABC exporters are functionally grouped into protein, peptide, and non-protein substrate transporters.
• Phylogenetic analysis reveals two primary branches of bacterial ABC exporters based on domain organization (single vs. separate polypeptides).

Conclusions:

• Bacterial ABC exporters represent a diverse and significant group of transport systems.
• The classification based on substrate type provides a framework for understanding their diverse roles.
• Evolutionary analysis highlights distinct organizational strategies within this protein superfamily.