Role of interstrand loops in the formation of intramolecular cross-β-sheets by homopolymino acids
✍ Scribed by Wayne L. Mattice; Harold A. Scheraga
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 1985
- Tongue
- English
- Weight
- 685 KB
- Volume
- 24
- Category
- Article
- ISSN
- 0006-3525
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✦ Synopsis
A matrix treatment of the formation of intramolecular anti-parallel P-sheets from a statistical coil has been extended to incorporate interstrand loops of arbitrary size. The behavior of the model is compared with a simpler version in which all pairs of contiguous strands were connected by P-bends. When large interstrand loops are allowed, there are many more types of sheets than is the case when all contiguous strands must be connected by tight or P-bends. For this reason, the larger interstrand loops make it easier to introduce the initial sheet into a statistical coil, and the sheet content is enhanced in the early stages of sheet formation ke., at small values of the growth parameter t). As the transition continues (i.e., as t increases), a stage will be reached where occupancy of the statistical coil state is negligible because nearly all residues are in sheets or interstrand loops. Now, additional sheet formation can be accomplished only at the expense of residues in the interior of interstrand loops. For this reason, the larger interstrand loops make it more difficult to complete the final stages of sheet formation. These effects are especially dramatic in the formation of cross-P-sheets.