title: Protonation states of buried histidine residues in human deoxyhemoglobin revealed by neutron crystallography.
abstract: The protonation states of buried histidine residues in human deoxyhemoglobin were unambiguously identified by using a neutron crystallographic technique. Unexpectedly, the neutron structure reveals that both the alpha- and beta-distal histidines (Hisalpha58 and Hisbeta63) adopt a positively charged, fully (doubly) protonated form, suggesting their contribution to the Bohr effect. In addition, the neutron data provide an accurate picture of the alpha1beta1 hydrogen-bonding network and allow us to observe unambiguously the nature of the intradimeric interactions at an atomic level.
authors.affiliation: Research Reactor Institute, Kyoto University, Kumatori, Osaka 590-0494, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Chatake
authors.forename: Naoya
authors.initials: N
authors.lastname: Shibayama
authors.forename: Sam-Yong
authors.initials: SY
authors.lastname: Park
authors.forename: Kazuo
authors.initials: K
authors.lastname: Kurihara
authors.forename: Taro
authors.initials: T
authors.lastname: Tamada
authors.forename: Ichiro
authors.initials: I
authors.lastname: Tanaka
authors.forename: Nobuo
authors.initials: N
authors.lastname: Niimura
authors.forename: Ryota
authors.initials: R
authors.lastname: Kuroki
authors.forename: Yukio
authors.initials: Y
authors.lastname: Morimoto
mesh_terms: D006454:Hemoglobins / Q000737:chemistry*; D006639:Histidine / Q000737:chemistry*; D006801:Humans; D008958:Models, Molecular; D033363:Neutron Diffraction; D017434:Protein Structure, Tertiary; D011522:Protons
chemical_list: D006454:Hemoglobins; D011522:Protons; D006639:Histidine; C100003:deoxyhemoglobin