Carboxyl group hydrogen bonding in X-ray protein structures analysed using neutron studies on amino acids.
A method is proposed to make a distinction between ionized and neutral carboxyl groups in X-ray protein structures. This is based on an analysis of the relative hydrogen bonding populations and bond-length bond-valence correlations in high-precision neutron studies of amino acids and small peptides. With the help of this method, four amino acid residues containing carboxyl groups in the refined structure of triclinic hen egg-white lysozyme have been analysed. Two of these, Glu-35 and Asp-52, are involved in lysozyme function, while the other two, Glu-7 and Asp-101, form a protein-protein inter-molecular contact in the triclinic structure.
Solid State Physics Division, Bhabha Atomic Research Centre, Trombay, Bombay, India.
M
M
Ramanadham
V S
VS
Jakkal
R
R
Chidambaram
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000737:chemistry*; D000818:Animals; D002645:Chickens; D006860:Hydrogen Bonding; D009113:Muramidase / Q000737:chemistry*; D011487:Protein Conformation; D011506:Proteins / Q000737:chemistry*; D014961:X-Ray Diffraction / Q000379:methods
D000596:Amino Acids; D011506:Proteins; D009113:Muramidase