title: Hydrogen and hydration in proteins.
abstract: Neutron diffraction provides an experimental method of directly locating hydrogen atoms in proteins. High-resolution neutron diffractometers dedicated to biological macromolecules (BIX-type diffractometer) have been constructed at the Japan Atomic Energy Research Institute and they have been used in the 1.5A-resolution crystal structure analyses of several proteins. Interesting topics relevant to hydrogen and hydration in proteins, such as (1) the detailed geometry of hydrogen bonds; (2) information regarding hydrogen/deuterium exchange behavior; (3) the acidities of certain H atoms; (4) the role of hydrogen atoms in enzyme mechanisms and thermostability; (5) the location methyl hydrogen atoms; and (6) dynamical behavior of hydration structures that include H positions have been extracted from these structural results. In addition, a method for the systematic growth of large single crystals based on phase diagrams has been introduced and will be briefly described in this article.
authors.affiliation: Neutron Science Research Center, Japan Atomic Energy Research Institute, Shirane, Tokai-mura, Naka-gun, Ibaraki-ken, Japan. niimura@kotai3.tokai.jaeri.go.jp
authors.forename: Nobuo
authors.initials: N
authors.lastname: Niimura
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Chatake
authors.forename: Kazuo
authors.initials: K
authors.lastname: Kurihara
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Maeda
mesh_terms: D003460:Crystallization; D018360:Crystallography, X-Ray; D003903:Deuterium; D004355:Drug Stability; D004798:Enzymes / Q000737:chemistry; D006639:Histidine / Q000737:chemistry; D006859:Hydrogen / Q000737:chemistry; D006860:Hydrogen Bonding; D008958:Models, Molecular; D033363:Neutron Diffraction; D011506:Proteins / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D004798:Enzymes; D011506:Proteins; D014867:Water; D006639:Histidine; D006859:Hydrogen; D003903:Deuterium