title: Hell's Gate globin I: an acid and thermostable bacterial hemoglobin resembling mammalian neuroglobin.
abstract: Hell's Gate globin I (HGbI), a heme-containing protein structurally homologous to mammalian neuroglobins, has been identified from an acidophilic and thermophilic obligate methanotroph, Methylacidiphilum infernorum. HGbI has very high affinity for O(2) and shows barely detectable autoxidation in the pH range of 5.2-8.6 and temperature range of 25-50°C. Examination of the heme pocket by X-ray crystallography and molecular dynamics showed that conformational movements of Tyr29(B10) and Gln50(E7), as well as structural flexibility of the GH loop and H-helix, may play a role in modulating its ligand binding behavior. Bacterial HGbI's unique resistance to the sort of extreme acidity that would extract heme from any other hemoglobin makes it an ideal candidate for comparative structure-function studies of the expanding globin superfamily.
authors.affiliation: Centre for Chemical Biology, Universiti Sains Malaysia, Bayan Lepas, Penang, Malaysia.
authors.forename: Aik-Hong
authors.initials: AH
authors.lastname: Teh
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Saito
authors.forename: Aida
authors.initials: A
authors.lastname: Baharuddin
authors.forename: Jason R
authors.initials: JR
authors.lastname: Tuckerman
authors.forename: James S
authors.initials: JS
authors.lastname: Newhouse
authors.forename: Masaomi
authors.initials: M
authors.lastname: Kanbe
authors.forename: Elizabeth I
authors.initials: EI
authors.lastname: Newhouse
authors.forename: Rashidah Abdul
authors.initials: RA
authors.lastname: Rahim
authors.forename: Frédérique
authors.initials: F
authors.lastname: Favier
authors.forename: Claude
authors.initials: C
authors.lastname: Didierjean
authors.forename: Eduardo H S
authors.initials: EH
authors.lastname: Sousa
authors.forename: Matthew B
authors.initials: MB
authors.lastname: Stott
authors.forename: Peter F
authors.initials: PF
authors.lastname: Dunfield
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Gonzalez
authors.forename: Marie-Alda
authors.initials: MA
authors.lastname: Gilles-Gonzalez
authors.forename: Nazalan
authors.initials: N
authors.lastname: Najimudin
authors.forename: Maqsudul
authors.initials: M
authors.lastname: Alam
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry*; D018360:Crystallography, X-Ray; D005914:Globins / Q000737:chemistry; D006090:Gram-Negative Bacteria / Q000737:chemistry*; D006454:Hemoglobins / Q000737:chemistry*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009419:Nerve Tissue Proteins / Q000737:chemistry; D000078787:Neuroglobin; D010100:Oxygen / Q000737:chemistry; D017434:Protein Structure, Tertiary; D040681:Structural Homology, Protein; D013329:Structure-Activity Relationship
chemical_list: D001426:Bacterial Proteins; D006454:Hemoglobins; D009419:Nerve Tissue Proteins; D000078787:Neuroglobin; D005914:Globins; D010100:Oxygen