Channel restriction of OmpK36 variants.

Comparison of the reference OmpK36 structure under PDB accession 5nupA (A) against predicted structural models of OmpK36 (B) and OmpK36GD mutant (C) from ATCC 13883, showing progressive restriction of the porin channel. The conformation visualised in panel B, in particular the loop 6 in yellow which can be seen partially obstructing the channel, is not associated with a carbapenem resistance phenotype, contrary to the GD mutant shown in panel C. Panel D consists of the multiple alignment of the 3 corresponding sequences, along with a representation of the predicted secondary structures designated as follows; B for barrel, T for turn, and L for loop. Signal peptide is not shown in 5nupA sequence (Panel D).