  Many types of peripheral and transmembrane proteins can sense and generate
membrane curvature. Laterally isotropic proteins and crescent proteins with
twofold rotational symmetry, such as Bin/Amphiphysin/Rvs superfamily proteins,
have been studied theoretically. However, proteins often have an asymmetric
structure or a higher rotational symmetry. We theoretically studied the
curvature sensing of proteins with asymmetric structures and structural
deformations. First, we examined proteins consisting of two rod-like segments.
When proteins have mirror symmetry, their sensing ability is similar to that of
single-rod proteins; hence, with increasing protein density on a cylindrical
membrane tube, a second- or first-order transition occurs at a middle or small
tube radius, respectively. As asymmetry is introduced, this transition becomes
a continuous change, and metastable states appear at high protein densities.
Protein with threefold, fivefold, or higher rotational symmetry has laterally
isotropic bending energy. However, when a structural deformation is allowed,
the protein can have a preferred orientation and stronger curvature sensing.
