Prions
Not all infectious diseases are transmitted by bacteria or viruses. Some neurological diseases, such as Creutzfeldt-Jaakob disease (CJD) or mad cow disease are in fact caused by agents called Prions, which are of similar size to viruses but are made up of only protein [1]
Prions have these characteristics:
1.) "The transmissible agent consists of aggregated forms of a specific protein" [2].
2.) These protein aggregates cannot be degraded by the agents that degrade most other proteins [3].
3.) "The protein is largely or completely derived from a cellular protein called PrP, that is normally present in the brain" [4].
So an aggregated form of a protein (that is already present in the brain) is the infectious agent in prion diseases [5].
The pathalogic mechanism of prions is often associated with structural change. Exogenous prions cause the endogenous host proteins to undergo a structural change, rendering them functionless or harmful.
References
- ↑ J. M. Berg et al. (2007) p 53, Biochemistry, Sixth edition, New York, W.H. Freeman and Company
- ↑ J. M. Berg et al. (2007) p 53, Biochemistry, Sixth edition, New York, W.H. Freeman and Company
- ↑ J. M. Berg et al. (2007) p 53, Biochemistry, Sixth edition, New York, W.H. Freeman and Company
- ↑ J. M. Berg et al. (2007) p 53, Biochemistry, Sixth edition, New York, W.H. Freeman and Company
- ↑ J. M. Berg et al. (2007) p 54, Biochemistry, Sixth edition, New York, W.H. Freeman and Company