Fig. 2
From: Outer membrane protein folding from an energy landscape perspective
Requirements for OMPs to fold to a stable and functional state. Clockwise from top: (i) OmpX (2MO6 [222], grey)—hydrophobic residues are shown as orange sticks; (ii) OmpLA (1QD6 [226], blue) in a dimyristoylphosphatidylethanolamine (DMPE; diC14:0PE) bilayer (from [234]); (iii) alignment of BamA β-barrel structures in the ‘lateral open’ (5D0Q [78], green) and ‘lateral closed’ (5D0O [78], yellow) states; (iv) OmpF (2OMF [229])—monomers in the trimeric structure are shown in red, yellow and blue; (v) FhuA (1FI1 [235], pink)—bound LPS is shown as yellow sticks; (vi) OmpT (1I78 [224], green cartoon)—regions of red and blue represent areas of electronegative and electropositive surface potential (−1 kT/e to +1 kT/e) and were created using the APBS plugin for PyMOL [236]; (vii) PagP (3GP6 [237], orange)—conserved residues important in enzymatic function, H33, D76 and S77 (pink, green and cyan, respectively), are highlighted; (viii) free energy diagram showing the difference in stability of the folded (F) and unfolded (U) states; (ix) LptD (4N4R [37], lime green)—Trp residues are shown as red sticks. The central image shows the transmembrane domain of OmpA (1QJP [223], with mutated residues in the structure replaced with wild-type residues and missing residues in the loops built in using MODELLER [238]) in a DMPE bilayer (taken from [234])