ChemInform Abstract: QUANTUM THEORY OF THE STRUCTURE AND BONDING IN PROTEINS. PART 7. THE α HELIX AND THE HYDROGEN BONDING IN THE TETRAPEPTIDE

1981 ◽  
Vol 12 (9) ◽  
Author(s):  
D. PETERS ◽  
J. PETERS
Keyword(s):  
Hydrogen Bonding ◽  
Quantum Theory ◽  
Structure And Bonding ◽  
Α Helix

Structure, stability and folding of the α-helix

2001 ◽  
Vol 68 ◽  
pp. 95-110 ◽  
Author(s):  
Andrew J. Doig ◽  
Charles D. Andrew ◽  
Duncan A. E. Cochran ◽  
Eleri Hughes ◽  
Simon Penel ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Hydrophobic Interactions ◽  
Data Bank ◽  
Site Directed Mutagenesis ◽  
Model Systems ◽  
Side Chain ◽  
Structure Stability ◽  
Helical Peptides ◽  
Vast Number ◽  
Α Helix

Pauling first described the α-helix nearly 50 years ago, yet new features of its structure continue to be discovered, using peptide model systems, site-directed mutagenesis, advances in theory, the expansion of the Protein Data Bank and new experimental techniques. Helical peptides in solution form a vast number of structures, including fully helical, fully coiled and partly helical. To interpret peptide results quantitatively it is essential to use a helix/coil model that includes the stabilities of all these conformations. Our models now include terms for helix interiors, capping, side-chain interactions, N-termini and 310-helices. The first three amino acids in a helix (N1, N2 and N3) and the preceding N-cap are unique, as their amide NH groups do not participate in backbone hydrogen bonding. We surveyed their structures in proteins and measured their amino acid preferences. The results are predominantly rationalized by hydrogen bonding to the free NH groups. Stabilizing side-chain-side-chain energies, including hydrophobic interactions, hydrogen bonding and polar/non-polar interactions, were measured accurately in helical peptides. Helices in proteins show a preference for having approximately an integral number of turns so that their N- and C-caps lie on the same side. There are also strong periodic trends in the likelihood of terminating a helix with a Schellman or αL C-cap motif. The kinetics of α-helix folding have been studied with stopped-flow deep ultraviolet circular dichroism using synchrotron radiation as the light source; this gives a far superior signal-to-noise ratio than a conventional instrument. We find that poly(Glu), poly(Lys) and alanine-based peptides fold in milliseconds, with longer peptides showing a transient overshoot in helix content.

scholarly journals Direct NMR Detection of Bifurcated Hydrogen Bonding in the α-Helix N-Caps of Ankyrin Repeat Proteins

2015 ◽  
Vol 137 (3) ◽  
pp. 1008-1011 ◽  
Author(s):  
Matthew R. Preimesberger ◽  
Ananya Majumdar ◽  
Tural Aksel ◽  
Kevin Sforza ◽  
Thomas Lectka ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Ankyrin Repeat ◽  
Repeat Proteins ◽  
Ankyrin Repeat Proteins ◽  
Α Helix
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