title: Hydrogen bonds of DsrD protein revealed by neutron crystallography.
abstract: The features of hydrogen bonds in DsrD protein from sulfate-reducing bacteria have been investigated by neutron protein crystallography. The function of DsrD has not yet been elucidated clearly, but its X-ray crystal structure revealed that it comprises a winged-helix motif and shows the highest structural homology to the DNA-binding proteins. Since any neutron structure of a DNA recognition protein has not yet been obtained, here detailed information on the hydrogen bonds in the winged-helix-motif protein is given and the following features found. (i) The number of hydrogen bonds per amino acid of DsrD is relatively fewer than for other proteins for which neutron structures were determined previously. (ii) Hydrogen bonds are localized between main-chain and main-chain atoms; there are few hydrogen bonds between main-chain and side-chain atoms and between side-chain and side-chain atoms. (iii) Hydrogen bonds inducted by protonation of specific amino acid residues (Glu50) seem to play an essential role in the dimerization of DsrD. The former two points are related to the function of the DNA-binding protein; the three-dimensional structure was mainly constructed by hydrogen bonds in main chains, while the side chains appeared to be used for another role. The latter point would be expected to contribute to the crystal growth of DsrD.
authors.affiliation: Kyoto University, Research Reactor Institute, Asashironishi 2, Kumatori, Sennan-gun, Osaka 590-0494, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Chatake
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Higuchi
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Mizuno
authors.forename: Ichiro
authors.initials: I
authors.lastname: Tanaka
authors.forename: Nobuo
authors.initials: N
authors.lastname: Niimura
authors.forename: Yukio
authors.initials: Y
authors.lastname: Morimoto
mesh_terms: D018360:Crystallography, X-Ray / Q000379:methods*; D019281:Dimerization; D006860:Hydrogen Bonding; D050885:Hydrogensulfite Reductase / Q000737:chemistry*; D008958:Models, Molecular; D009502:Neutrons; D011487:Protein Conformation
chemical_list: D050885:Hydrogensulfite Reductase