Mass spectrometry defines the C-terminal dimerization domain and enables modeling of the structure of full-length OmpA

Journal article

The transmembrane domain of the outer membrane protein A (OmpA) from Escherichia coli is an excellent model for structural and folding studies of β-barrel membrane proteins. However, full-length OmpA resists crystallographic efforts, and the link between its function and tertiary structure remains controversial. Here we use site-directed mutagenesis and mass spectrometry of different constructs of OmpA, released in the gas phase from detergent micelles, to define the minimal region encompassing the C-terminal dimer interface. Combining knowledge of the location of the dimeric interface with molecular modeling and ion mobility data allows us to propose a low-resolution model for the full-length OmpA dimer. Our model of the dimer is in remarkable agreement with experimental ion mobility data, with none of the unfolding or collapse observed for full-length monomeric OmpA, implying that dimer formation stabilizes the overall structure and prevents collapse of the flexible linker that connects the two domains. © 2014 Elsevier Ltd.

Authors: Marcoux, J; Politis, A; Rinehart, D; Marshall, D; Wallace, M

• Publisher: Cell Press
• Journal: Structure
• Volume: 22
• Issue: 5
• Pages: 781-790
• Publication date: 2014-05-06
• DOI: 10.1016/j.str.2014.03.004
• EISSN: 1878-4186
• ISSN: 0969-2126
• Language: English