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α-Helix nucleation by a calcium-binding peptide loop

Title data

Siedlecka, Monika ; Goch, Grażyna ; Ejchart, Andrzej ; Sticht, Heinrich ; Bierzyǹski, Andrzej:
α-Helix nucleation by a calcium-binding peptide loop.
In: Proceedings of the National Academy of Sciences of the United States of America. Vol. 96 (February 1999) Issue 3 . - pp. 903-908.
ISSN 1091-6490
DOI: https://doi.org/10.1073/pnas.96.3.903

Abstract in another language

A 12-residue peptide AcDKDGDGYISAAENH2 analogous to the third calcium-binding loop of calmodulin strongly coordinates lanthanide ions (K = 105 M−1). When metal saturated, the peptide adopts a very rigid structure, the same as in the native protein, with three last residues AAE fixed in the α-helical conformation. Therefore, the peptide provides an ideal helix nucleation site for peptide segments attached to its C terminus. NMR and CD investigations of peptide AcDKDGDGYISAAEAAAQNH2 presented in this paper show that residues A13-Q16 form an α-helix of very high stability when the La3+ ion is bound to the D1-E12 loop. In fact, the lowest estimates of the helix content in this segment give values of at least 80% at 1°C and 70% at 25°C. This finding is not compatible with existing helix-coil transition theories and helix propagation parameters, s, reported in the literature. We conclude, therefore, that the initial steps of helix propagation are characterized by much larger s values, whereas helix nucleation is even more unfavorable than is believed. In light of our findings, thermodynamics of the nascent α-helices is discussed. The problem of CD spectra of very short α-helices is also addressed.

Further data

Item Type: Article in a journal
Refereed: Yes
Institutions of the University: Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry > Former Professors > Chair Biopolymers - Univ.-Prof. Dr. Paul Rösch
Faculties
Faculties > Faculty of Biology, Chemistry and Earth Sciences
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry > Former Professors
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry > Chair Biopolymers
Result of work at the UBT: Yes
DDC Subjects: 500 Science > 540 Chemistry
500 Science > 570 Life sciences, biology
Date Deposited: 23 Jan 2019 11:13
Last Modified: 29 Oct 2019 10:24
URI: https://eref.uni-bayreuth.de/id/eprint/46999