کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5370962 | 1503920 | 2015 | 8 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: On the roles of the alanine and serine in the β-sheet structure of fibroin On the roles of the alanine and serine in the β-sheet structure of fibroin](/preview/png/5370962.png)
- Semiempirical MP6, DFT calculations and molecular dynamics calculations on fibroin type models are provided.
- These results show how alanine and serine impact the rigidity of β-sheet structures.
- Alanine adds stability to the rigidity of the sheet, allowing it to maintain a properly pleated structure even in a single β-sheet.
- The role of the serine is proposed to involve modulation of the hydrophobicity.
In its silk II form, fibroin is almost exclusively formed from layers of β-sheets, rich in glycine, alanine and serine. Reported here are computational results on fibroin models at semi-empirical, DFT levels of theory and molecular dynamics (MD) for (Gly)10, (Gly-Ala)5 and (Gly-Ser)5 decapeptides. While alanine and serine introduce steric repulsions, the alanine side-chain adds to the rigidity of the sheet, allowing it to maintain a properly pleated structure even in a single β-sheet, and thus avoiding two alternative conformations which would interfere with the formation of the multi-layer pleated-sheet structure. The role of the serine is proposed to involve modulation of the hydrophobicity in order to construct the supramolecular assembly as opposed to random precipitation due to hydrophobicity.
Journal: Biophysical Chemistry - Volume 197, February 2015, Pages 10-17