Cellular cells require mechanisms for safeguarding newly synthesized and incompletely folded proteins. These mechanisms are now under intensive research, with a class of proteins referred to as molecular chaperones the central player. Molecular chaperones are a family of folding modulators that play a crucial role in cellular processes. Molecular chaperones play a significant role in protein folding and cellular viability as it helps proteins to fold correctly into their functional native forms (Hartl, Bracher, & Hayer-Hartl, 2011). This paper will discuss why Fieldman and Frydman consider molecular chaperones critical for protein folding. In this paper, a unique assignment will be created, which will be used as a check for understanding for students when learning about molecular chaperones. Molecular proteins, such as heat shock proteins (HSP), aid in the folding of newly synthesized polypeptide chains (Feldman & Frydman, 2000). More to this is that they help in the translocation of proteins across membranes. Usually, when proteins fold properly, chaperones are released. However, in some cases, these proteins are not released and thus remain bound to functionally folded proteins within the cell. However, it is vital to note that majority of proteins fold properly – only a few proteins require the help of chaperones in order to fold (Feldman & Frydman, 2000). Molecular chaperones help guide the folding of many proteins (Pockley, Calderwood, & Santoro, 2010). Without these proteins, a lot of intermediates protein folding pathways would aggregate. More to this is that would be left as off-path dead ends. The Hsp70 chaperone team is involved in a large variety of protein folding processes. Some of these processes include “de novo folding of newly synthesized polypeptides; refolding of spontaneously unfolded or stress misfolded proteins; dis-aggregation of protein aggregates; translocation of polypeptides across biological membranes” (Pockley, Calderwood, & Santoro, 2010). According to (Feldman & Frydman, 2000) Hsp70 plays a vital role in de novo folding. This is because the protein stabilizes a translating or translocating polypeptide in order to prevent the polypeptide from folding prematurely. Eukaryotes is composed of two major families, namely, Hps60 and Hsp70 (Saibil, 2013). Each of these two major families of eukaryotes works with its own set of proteins. However, it is worth noting that both Hsp60 and Hsp70 share an affinity for exposed hydrophobic patches on proteins that are incompletely folded (Saibil, 2013). More to this is that they both hydrolyse adenosine triphosphate (ATP). However, Hsp70 acts early while hsp60 acts later in the life of a protein. Hsp60 is barrel-shaped and this structure acts as an isolation chamber where proteins that are incompletely folded or misfolded can be fed in order to prevent aggregation as well as allow for refolding to occur in an appropriate environment (Pockley, Calderwood, & Santoro, 2010).
Molecular chaperones play a vital role in cellular processes. With regard to protein folding, molecular chaperones helps proteins to fold correctly into their functional native forms. The majority of proteins fold spontaneously, although there are few that require the help of molecular chaperones. Molecular proteins, such as HSP, aid in the folding of newly synthesized polypeptide chains. Hsp60 and Hsp70 help proteins that are incompletely folded to fold correctly into their functional native forms.
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References
Feldman, D., & Frydman, J. (2000). Protein folding in vivo: the importance of molecular chaperones. Current Opinion in Structural Biology, 10 (1): 26-33. DOI: 10.1016/s0959-440x(99)00044-5.
Hartl, F., Bracher, A., & Hayer-Hartl., M. (2011). Molecular chaperones in protein folding and proteostasis. PubMed, 475 (7356): 324-332. DOI: 10.1038/nature10317.
Pockley, A., Calderwood, S., & Santoro, M. (2010). Prokaryotic and eukaryotic heat shock proteins in infectious disease. Heiderlberg: London. Springer.
Saibil, H. (2013). Chaperone machines for protein folding, unfolding and disaggregation. Nature Reviews Molecular Cell Biology, 14 (10): 630-642. DOI: 10.1038/nrm3658 .
