  Prion diseases are invariably fatal and highly infectious neurodegenerative
diseases affecting humans and animals. The neurodegenerative diseases such as
Creutzfeldt-Jakob disease, variant Creutzfeldt-Jakob diseases,
Gerstmann-Str$\ddot{a}$ussler-Scheinker syndrome, Fatal Familial Insomnia, Kuru
in humans, scrapie in sheep, bovine spongiform encephalopathy (or 'mad-cow'
disease) and chronic wasting disease in cattle belong to prion diseases. By now
there have not been some effective therapeutic approaches to treat all these
prion diseases. Dogs, rabbits and horses were reported to be resistant to prion
diseases. By the end of year 2010 all the NMR structures of dog, rabbit and
horse prion proteins (X-ray for rabbits too) had been finished to release into
protein data bank. Thus, at this moment it is very worth studying the NMR and
X-ray molecular structures of horse, dog and rabbit prion proteins to obtain
insights into their immunity prion diseases.
  The author found that dog and horse prion proteins have stable molecular
dynamical structures whether under neutral or low pH environments, but rabbit
prion protein has stable molecular dynamical structures only under neutral pH
environment. Under low pH environment, the stable $\alpha$-helical molecular
structures of rabbit prion protein collapse into $\beta$-sheet structures. This
article focuses the studies on rabbit prion protein (within its C-terminal NMR,
Homology and X-ray molecular structured region RaPrP$^\text{C}$ (120-230)),
compared with human and mouse prion proteins (HuPrP$^\text{C}$ (125-228) and
MoPrP$^\text{C}$ (124-226) respectively). The author finds that some salt
bridges contribute to the structural stability of rabbit prion protein under
neutral pH environment.
