title: Local and macroscopic electrostatic interactions in single α-helices.
abstract: The noncovalent forces that stabilize protein structures are not fully understood. One way to address this is to study equilibria between unfolded states and α-helices in peptides. Electrostatic forces-which include interactions between side chains, the backbone and side chains, and side chains and the helix macrodipole-are believed to contribute to these equilibria. Here we probe these interactions experimentally using designed peptides. We find that both terminal backbone-side chain and certain side chain-side chain interactions (which include both local effects between proximal charges and interatomic contacts) contribute much more to helix stability than side chain-helix macrodipole electrostatics, which are believed to operate at larger distances. This has implications for current descriptions of helix stability, the understanding of protein folding and the refinement of force fields for biomolecular modeling and simulations. In addition, this study sheds light on the stability of rod-like structures formed by single α-helices, which are common in natural proteins such as non-muscle myosins.
authors: School of Chemistry, University of Bristol, Bristol, UK.
authors: Emily G
authors: EG
authors: Baker
authors: School of Chemistry, University of Bristol, Bristol, UK.
authors: Gail J
authors: GJ
authors: Bartlett
authors: School of Chemistry, University of Bristol, Bristol, UK.
authors: Matthew P
authors: MP
authors: Crump
authors: School of Biochemistry, University of Bristol, Bristol, UK.
authors: Richard B
authors: RB
authors: Sessions
authors: School of Mathematics, University of Bristol, Bristol, UK.
authors: Noah
authors: N
authors: Linden
authors: School of Chemistry, University of Bristol, Bristol, UK.
authors: Charl F J
authors: CF
authors: Faul
authors: 1] School of Chemistry, University of Bristol, Bristol, UK. [2] School of Biochemistry, University of Bristol, Bristol, UK.
authors: Derek N
authors: DN
authors: Woolfson
mesh_terms: D000595:Amino Acid Sequence; D019295:Computational Biology; D018698:Glutamic Acid / Q000737:chemistry; D008239:Lysine / Q000737:chemistry; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009218:Myosins / Q000737:chemistry; D010455:Peptides / Q000737:chemistry*; D017510:Protein Folding; D017433:Protein Structure, Secondary; D058767:Protein Unfolding; D055672:Static Electricity
chemical_list: D010455:Peptides; D018698:Glutamic Acid; D009218:Myosins; D008239:Lysine