Chaperone molecules models

Several different domains within a single precursor molecule are likely to interact simultaneously with the multiple binding sites on a single tetramer of the chaperone. The overall affinity will therefore be the result of several interactions of varying strength, some of which may be quite weak individually. This type of binding could be described as a zipper model in the sense that the strength of a zipper is the result of many weak interactions. 

The central premise upon which the modelling of proteins rests is that the 3D structure of a protein is determined by only its sequence and its enviroiunent, without the obligatory role of external factors. Reality is known to be more complex than this because, although many proteins have been refolded into their active forms, chaperones and disulphide interchange enzymes have been identified as assisting the folding process. However, it is generally considered that such molecules merely aid rather than dictate the final fold. ... 

Fig. 1. Alternative models of HCMV gpUS6 interaction with the transient TAP complex containing peptide-free MHC I molecules and ER-resident chaperones. According to a minimal model , gpUS6 binds directly to TAP itself left). The cofactor models depict scenarios in which gpUS6 does not bind physically to TAP but to a protein present in the TAP complex center) or gpUS6 recruits an unrelated molecule, e.g., calnexin, to TAP right), resulting in functional inactivation of peptide transport. ER, endoplasmic reticulum p2-microglobulin. See text for details...

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