Intramolecular backbone center dot center dot center dot backbone hydrogen bonds in polypeptide conformations. The other way around: epsilon-turn
Toniolo_et_al-2017-Peptide_Science.pdf (2,070Mb) (Restricted access) Request copy
Què és aquest botó?
Aquest botó permet demanar una còpia d'un document restringit a l'autor. Es mostra quan:
- Disposem del correu electrònic de l'autor
- El document té una mida inferior a 20 Mb
- Es tracta d'un document d'accés restringit per decisió de l'autor o d'un document d'accés restringit per política de l'editorial
Rights accessRestricted access - publisher's policy
In this study, we performed a detailed literature survey of the ¿-turn in peptides and proteins. This three-dimensional structural feature is characterized by an eleven-membered pseudo-cycle closed by an intramolecular backbone…backbone H-bond. Interestingly, in this motif the direction of the N-H…O¿=¿C H-bond runs opposite to that of the much more popular and extensively investigated a-, ß-, and ¿-turns. We did not authenticate unequivocally the ¿-turn main-chain reversal topology in any linear short peptide. However, it is frequently observed in small cyclic peptides formed by four, five, and six amino acid residues with stringent geometric requirements. Rather surprisingly, ¿-turns do occur in proteins, although to a relatively moderate extent, as an isolated feature or in the turn segment of hairpin motifs based on two antiparallel, pleated ß-strands. Moreover, the ¿-turn may also host not only the seven-membered, intramolecularly H-bonded, pseudo-cycle termed ¿-turn, either of the classic or inverse type, but also one (or even two) cis peptide bond(s) or a ß-bulge conformation. Based on their ¿, ¿ backbone torsion angles, we were able to classify the protein ¿-turns in six different families. Conformational energy computations using the DFT methodology were also performed on the ¿-turns adopted by the amino acid triplet -Gly-Gly-Gly- (Gly is the most commonly found residue at each of the three positions in our analysis of proteins). Again, in this computational study, six families of turns were identified, but only some of them resemble rather closely those extracted from our investigation on proteins.
CitationToniolo, C., Crisma, M., Formaggio, F., Aleman, C., Ramakrishnan, C., Kalmanar, N., Balaram, P. Intramolecular backbone center dot center dot center dot backbone hydrogen bonds in polypeptide conformations. The other way around: epsilon-turn. "Biopolymers", 1 Gener 2017, vol. 108, núm. 1.
All rights reserved. This work is protected by the corresponding intellectual and industrial property rights. Without prejudice to any existing legal exemptions, reproduction, distribution, public communication or transformation of this work are prohibited without permission of the copyright holder