Hydrogen bonding on the ice-binding face of a beta-helical antifreeze protein indicated by amide proton NMR chemical shifts.
The dependence of amide proton chemical shifts on temperature is used as an indication of the hydrogen bonding properties in a protein. The amide proton temperature coefficients of the beta-helical antifreeze protein from Tenebrio molitor are examined to determine their hydrogen bonding state in solution. The temperature-dependent chemical shift behavior of the amides in T. molitor antifreeze protein varies widely throughout the protein backbone; however, very subtle effects of hydrogen bonding can be distinguished using a plot of chemical shift deviation (CSD) versus the backbone amide chemical shift temperature gradient (Deltadelta/DeltaT). We show that differences between the two ranks of ice-binding threonine residues on the surface of the protein indicate that threonine residues in the left-hand rank participate in intrastrand hydrogen bonds that stabilize the flat surface required for optimal ice binding.
Daley
Margaret E
ME
Department of Biochemistry, CIHR Group in Protein Structure and Function, and Protein Engineering Network of Centres of Excellence, University of Alberta, Edmonton, Alberta T6G 2H7, Canada.
Graether
Steffen P
SP
Sykes
Brian D
BD
D000577:Amides / Q000737:chemistry*; D000595:Amino Acid Sequence; D000818:Animals; D021301:Antifreeze Proteins / Q000737:chemistry*; D006860:Hydrogen Bonding; D007053:Ice; D019476:Insect Proteins / Q000737:chemistry*; D008969:Molecular Sequence Data; D009587:Nitrogen Isotopes / Q000737:chemistry; D019906:Nuclear Magnetic Resonance, Biomolecular; D011485:Protein Binding; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D011522:Protons; D013696:Temperature; D013712:Tenebrio; D013816:Thermodynamics
D000577:Amides; D021301:Antifreeze Proteins; D007053:Ice; D019476:Insect Proteins; D009587:Nitrogen Isotopes; D011522:Protons