Structural and functional characteristics of the tripartite ABC transporter

Area of Science:

• Biochemistry and Molecular Biology
• Cell Biology
• Microbiology

Background:

• ATP-binding cassette (ABC) transporters constitute a vast protein superfamily involved in transmembrane transport across all domains of life.
• These proteins utilize ATP binding and hydrolysis to energize the movement of diverse substrates.
• Gram-negative bacteria possess unique ABC transporter systems, including the recently defined type VII class.

Approach:

• This review synthesizes current knowledge on the structural and functional characteristics of ABC transporters.
• Emphasis is placed on type VII ABC transporters, examining their assembly into tripartite complexes spanning both bacterial membranes.
• Structural analyses of specific transporters, such as the macrolide efflux transporter MacB, provide insights into their translocation mechanisms.

Key Points:

• Type VII ABC transporters form tripartite complexes, uniquely spanning the inner and outer membranes of Gram-negative bacteria.
• The macrolide efflux transporter MacB exemplifies the structural and functional features of this class.
• Recent structural studies elucidate the novel mechanisms employed by type VII ABC transporters for substrate translocation.

Conclusions:

• Type VII ABC transporters represent a distinct class with specialized structural adaptations for membrane transport in Gram-negative bacteria.
• Understanding the unique mechanisms of these transporters, exemplified by MacB, is crucial for deciphering complex cellular transport processes.
• Further structural and functional studies will illuminate the broader roles and potential applications of type VII ABC transporters.