A novel amphiphilic branched peptide (1), in which three beta-sheet formable peptides (L4K8L4) were connected by Lys residue, was newly prepared as a building block for self-assembly. A detailed analysis of the conformation and self-assembling property of 1 in water at various pH conditions was performed by using circular dichroism, FTIR, atomic force and transmission electron microscopies. The experimental results revealed that the branched peptide showed a pH-dependent conformation forming a shape-specific beta-sheet-based nanofiber with morphologically kinked structures under specific pH conditions. Exploring a novel peptide building unit that has the ability to self-assemble into designed and complicated nano-objects is valuable to facilitate a bottom-up nanotechnology. (c) 2011 Elsevier Inc. All rights reserved.