Nature has been a source of stimulation for the design of new biomaterials with desired mechanical properties. For example, native silk can possess a fracture toughness that is higher than that of steel, and human elastin is one of the most durable and resilient proteins with an estimated half-life of 70 years. By fusing polypeptide sequences derived from these two proteins, silk-elastin-like proteins (SELPs) have been genetically engineered for various biomedical applications. In the hybrid SELPs, the silk-like blocks can be crystallized, providing mechanical strength, while the elastin-like blocks enhance deformability by reducing crystallinity of the silk-like blocks. A combination of high mechanical strength and deformability could be achieved in a SELP by controlling the length and sequence of the silk- and elastin-like blocks and by regulating the crystallization process. The objective of this research is to understand the fundamental deformation mechanisms of SELPs, facilitating a rational design of new protein-based materials. To achieve this goal, the thermodynamics and kinetics of the SELP crystallization will be experimentally examined and its deformation under physiologically relevant conditions will be characterized. The proposed research will provide the necessary first step toward the molecular design and genetic engineering of new protein-based materials with desired mechanical properties. The potential of SELPs for various biomedical applications will be explored, where mechanical considerations are particularly relevant. Results from the research will be also integrated into a combined undergraduate and graduate course. Undergraduate and graduate students performing the research, including underrepresented minorities and women, will receive training in these emerging areas of biomechanics and biomaterials.