Misfolding and aggregation of the prion protein (PrP) is responsible for the development of fatal transmissible neurodegenerative diseases. PrP undergoes structural conversion from a natively folded state into a misfolded state, resulting in aggregated amyloid fibrils. Partial unfolding has been recognized as an essential step in fibrillation, especially at the middle point of unfolding. To study the possible aggregation-prone states, we characterized the structure of the C-terminal globular domain of human prion (huPrP) 121-230 near extended conformation at melting temperature by replica exchange molecular dynamics (REMD) simulation, as the REMD method is the most suited generalized-ensemble algorithm that performs random walk in energy space and promotes a system to escape from local energy traps. Our results revealed that denatured huPrP is partially folded with a-helical structure at melting temperature. The simulation results provide further insight into the unfolding of prion, which is essential in pathogenesis of prion diseases.