This is a tale of OmpA_omega_A (green) and Z_alpha (red). Omega and A as well as alpha and Z are joined by a linker. Z and A feel an affinity to each other and eagerly interact. Alpha and omega are not so straightforward and need to get to know before they get attracted, so it only happens after they are brought together by willingly attracting A and Z. And they lived happily ever after.
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