  Mechanical characterization of protein molecules has played a role on gaining
insight into the biological functions of proteins, since some proteins perform
the mechanical function. Here, we present the mesoscopic model of biological
protein materials composed of protein crystals prescribed by Go potential for
characterization of elastic behavior of protein materials. Specifically, we
consider the representative volume element (RVE) containing the protein
crystals represented by alpha-carbon atoms, prescribed by Go potential, with
application of constant normal strain to RVE. The stress-strain relationship
computed from virial stress theory provides the nonlinear elastic behavior of
protein materials and their mechanical properties such as Young's modulus,
quantitatively and/or qualitatively comparable to mechanical properties of
biological protein materials obtained from experiments and/or atomistic
simulations. Further, we discuss the role of native topology on the mechanical
properties of protein crystals. It is shown that parallel strands (hydrogen
bonds in parallel) enhances the mechanical resilience of protein materials.
