TY - JOUR

T1 - Probing the E/K Peptide Coiled-Coil Assembly by Double Electron-Electron Resonance and Circular Dichroism

AU - Golysheva, Elena A.

AU - Boyle, Aimee L.

AU - Biondi, Barbara

AU - Ruzza, Paolo

AU - Kros, Alexander

AU - Raap, Jan

AU - Toniolo, Claudio

AU - Formaggio, Fernando

AU - Dzuba, Sergei A.

N1 - Funding Information: E.A.G. was supported by RFBR Grant 19-33-90027. Publisher Copyright: © 2021 American Chemical Society. All rights reserved. Copyright: Copyright 2021 Elsevier B.V., All rights reserved.

PY - 2021/1/12

Y1 - 2021/1/12

N2 - Double electron-electron resonance (DEER, also known as PELDOR) and circular dichroism (CD) spectroscopies were explored for the purpose of studying the specificity of the conformation of peptides induced by their assembly into a self-recognizing system. The E and K peptides are known to form a coiled-coil heterodimer. Two paramagnetic TOAC α-amino acid residues were incorporated into each of the peptides (denoted as K*∗ and E**), and a three-dimensional structural investigation in the presence or absence of their unlabeled counterparts E and K was performed. The TOAC spin-labels, replacing two Ala residues in each compound, are covalently and quasi-rigidly connected to the peptide backbone. They are known not to disturb the native structure, so that any conformational change can easily be monitored and assigned. DEER spectroscopy enables the measurement of the intramolecular electron spin-spin distance distribution between the two TOAC labels, within a length range of 1.5-8 nm. This method allows the individual conformational changes for the K**, K**/E, E**, and E**/K molecules to be investigated in glassy frozen solutions. Our data reveal that the conformations of the E*∗ and K*∗ peptides are strongly influenced by the presence of their counterparts. The results are discussed with those from CD spectroscopy and with reference to the already reported nuclear magnetic resonance data. We conclude that the combined DEER/TOAC approach allows us to obtain accurate and reliable information about the conformation of the peptides before and after their assembly into coiled-coil heterodimers. Applications of this induced fit method to other two-component, but more complex, systems, like a receptor and antagonists, a receptor and a hormone, and an enzyme and a ligand, are discussed.

AB - Double electron-electron resonance (DEER, also known as PELDOR) and circular dichroism (CD) spectroscopies were explored for the purpose of studying the specificity of the conformation of peptides induced by their assembly into a self-recognizing system. The E and K peptides are known to form a coiled-coil heterodimer. Two paramagnetic TOAC α-amino acid residues were incorporated into each of the peptides (denoted as K*∗ and E**), and a three-dimensional structural investigation in the presence or absence of their unlabeled counterparts E and K was performed. The TOAC spin-labels, replacing two Ala residues in each compound, are covalently and quasi-rigidly connected to the peptide backbone. They are known not to disturb the native structure, so that any conformational change can easily be monitored and assigned. DEER spectroscopy enables the measurement of the intramolecular electron spin-spin distance distribution between the two TOAC labels, within a length range of 1.5-8 nm. This method allows the individual conformational changes for the K**, K**/E, E**, and E**/K molecules to be investigated in glassy frozen solutions. Our data reveal that the conformations of the E*∗ and K*∗ peptides are strongly influenced by the presence of their counterparts. The results are discussed with those from CD spectroscopy and with reference to the already reported nuclear magnetic resonance data. We conclude that the combined DEER/TOAC approach allows us to obtain accurate and reliable information about the conformation of the peptides before and after their assembly into coiled-coil heterodimers. Applications of this induced fit method to other two-component, but more complex, systems, like a receptor and antagonists, a receptor and a hormone, and an enzyme and a ligand, are discussed.

UR - http://www.scopus.com/inward/record.url?scp=85098763098&partnerID=8YFLogxK

U2 - 10.1021/acs.biochem.0c00773

DO - 10.1021/acs.biochem.0c00773

M3 - Article

C2 - 33320519

AN - SCOPUS:85098763098

VL - 60

SP - 19

EP - 30

JO - Biochemistry

JF - Biochemistry

SN - 0006-2960

IS - 1

ER -