The linear cationic ahelical peptide HP isolated from the N-terminal region of the Helicobacter pylori ribosomal protein can activate phagocyte NADPH oxidase to produce reactive oxygen species while being a neutrophil chemoattractant with bactericidal potency. A profound interest has been taken in non-receptor-mediated interaction of AMPs and target cell membrane, to reveal the mechanism regulating the action and activities of AMPs. It is believed that the antimicrobial activity is related to structural determinants, such as the peptide conformation, charge, hydrophobicity, amphipathicity and polar angle. For the action of AMPs, a rational theme is that, as the peptides meet a target cell, the positive charges are beneficial for them to be captured and bound to the cellular membrane by electrostatic affinity ; the bound peptides interact with the cellular membrane by their hydrophobic face, and may undergo a conformational phase transition in the framework of the cellular membrane via electrostatic, hydrophobic or other affinities ; but, the membrane pore or channel formation, which causes dysfunction of the cell, occurs just as the accumulation of the bound peptides on the cellular membrane has arrived at a stoichiometric threshold ; and then, the membrane disruption is induced, or the peptides would directly enter the membrane to access and inhibit intracellular targets. However, previous works were focused mainly on biochemical and biophysical aspects instead of mechanical correspondence in the interaction of the peptides and cellular membrane. In contrast, intuitively there may be a mechanical mechanism to regulate the action of AMPs. It was indicated that, the flexibility induced by the hinge sequence in the central part of the peptides would allow the a-helix in the C-terminus to closely span the lipid bilayer, and increase the antimicrobial activities, while the deletion of the hinge sequences will decrease the bactericidal rate significantly. The enhanced MK-1775 rigidity of the red cell membrane bound with ligands hints that, the rigidity of cellular membrane also may increase remarkably with the accumulation of the bound peptides, and then regulate the stretching and bending as well as the disruption of the membrane under loads. On the other hand, a stable structural conformation, which may be required for the interaction of AMP and membrane, refers to the spring constant of the peptide, and the conformational phase transition nearly always occurs in a mechanical environment. Besides, rigidity requirement is exhibited in many biological processes. For instance, in maintaining cell shape or aiding cell movement, a modest range of spring constant is required for cytoskeleton and diverse filaments in a cell ; the protein structure with an adequate rigidity may provide a foothold for the activation process of muscle contraction ; and, a rigid conformation for an enzyme molecule is required to hold its substrate in an activated conformation.