Biophysical Society Conference | Tahoe 2022

Molecular Biophysics of Membranes

Poster Abstracts

16-POS Board 4 COMPARING THE DYNAMICS OF THE BAM COMPLEX BETWEEN TWO SPECIES Zixing Fan 1 ; Zijian Zhang 2 ; Evan Billings 3 ; Nicholas Noinaj 3 ; James C Gumbart 2,4 ; 1 Georgia Institute of Technology, Bioengineering, Atlanta, GA, USA 2 Georgia Institute of Technology, Physics, Atlanta, GA, USA 3 Purdue University, Department of Biological Science, West Lafette, IN, USA 4 Georgia Institute of Technology, School of Chemistry and Biochemistry, Atlanta, GA, USA Outer membrane proteins (OMPs) in Gram- negative bacteria are transmembrane β -barrel proteins that are involved in important biological activities such as nutrient transport, signal transduction and the export of virulence factors. While it’s known that the protein complex responsible for assembly and insertion of OMPs into the outer membrane is the β -barrel assembly machinery (BAM), the detailed mechanisms for OMP insertion by BAM are only recently coming into focus. Nonetheless, to date, the only complete high-resolution structures of BAM are from Escherichia coli, leaving open the question of the degree of conservation of mechanisms across species. To shed light on these issues, we have carried out microsecond-scale molecular dynamics simulations of a newly resolved structure of the BAM complex from Neisseria gonorrheae to identify key interactions between BAM components relevant for the insertion process. The structure of BAM from N. gonorrheae, solved by cryo-electron microscopy, shares many similarities with that from E. coli, although the former species lacks the accessory protein, BamB, which may play a stabilizing role in the E. coli BAM complex according to our simulations. Finally, we compare the results of simulations of both BAM complexes to identify general mechanisms across different species, and the results will be discussed.

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