Journal
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS
Volume 494, Issue 3-4, Pages 668-673Publisher
ACADEMIC PRESS INC ELSEVIER SCIENCE
DOI: 10.1016/j.bbrc.2017.10.102
Keywords
Escherichia coli; Actinobacillus actinomycetemcomitans; Tripartite efflux pump; MacAB-TolC; Electron microscopy
Categories
Funding
- National Research Foundation of Korea [NRF-2017H1A2A1042661, 2017R1A2B2003992, 2017R1A2B2011008]
- National Research Foundation of Korea [2017H1A2A1042661, 2017R1A2B2011008, 2017R1A2B2003992] Funding Source: Korea Institute of Science & Technology Information (KISTI), National Science & Technology Information Service (NTIS)
Ask authors/readers for more resources
The MacAB-TolC tripartite efflux pump is involved in resistance to macrolide antibiotics and secretion of protein toxins in many Gram-negative bacteria. The pump spans the entire cell envelope and operates by expelling substances to extracellular space. X-ray crystal and electron microscopic structures have revealed the funnel-like MacA hexamer in the periplasmic space and the cylindrical TolC trimer. Nonetheless, the inner membrane transporter MacB still remains ambiguous in terms of its oligomeric state in the functional complex. In this study, we purified a stable binary complex using a fusion protein of MacA and MacB of Escherichia coli, and then supplemented MacA to meet the correct stoichiometry between the two proteins. The result demonstrated that MacB is a homodimer in the complex, which is consistent with results from the recent complex structure using cryo-electron microscopy single particle analysis. Structural comparison with the previously reported MacB periplasmic domain structure suggests a molecular mechanism for regulation of the activity of MacB via an interaction between the MacB periplasmic domain and MacA. Our results provide a better understanding of the tripartite pumps at the molecular level. (C) 2017 Elsevier Inc. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available