Biomaterial Database

Ligand migration in sperm whale myoglobin. 1997

E E Scott, and Q H Gibson

Department of Biochemistry and Cell Biology, Rice University, 6100 Main Street, Houston, Texas 77005, USA. yertle@bioc.rice.edu

Geminate oxygen rebinding to myoglobin was followed from a few nanoseconds to a few microseconds after photolysis for more than 25 different oxymyoglobin point mutants in the presence and absence of 12 atm of xenon. In all cases, two relaxations were observed: an initial fast phase (half-time 20 ns) and a slower, smaller phase (half-time 0.5-2 micros). Generally, xenon accelerates the fast reaction but slows the slower reaction and diminishes its amplitude. The rates and proportions of the two components and the effects of xenon on them vary widely for different mutants. The locations of specific xenon binding sites [Tilton, R. F., Kuntz, I. D. Jr., and Petsko, G. A. (1984) Biochemistry 23, 2849-2857], the effects of point mutations on the geminate reactions, and molecular dynamics simulations were used to suggest locations in the protein interior occupied by ligands on the nanosecond to microsecond time scale. Photodissociated ligands may occupy xenon site 4 in the distal pocket and xenon site 1 below the plane of the heme. Rebinding from these positions corresponds to the slower geminate phase for O2 rebinding. The rapid geminate component is determined by competition between rebinding from a position closer to the iron atom and escape to solvent or more distant locations in the protein.

UI	MeSH Term	Description	Entries
D008024	Ligands	A molecule that binds to another molecule, used especially to refer to a small molecule that binds specifically to a larger molecule, e.g., an antigen binding to an antibody, a hormone or neurotransmitter binding to a receptor, or a substrate or allosteric effector binding to an enzyme. Ligands are also molecules that donate or accept a pair of electrons to form a coordinate covalent bond with the central metal atom of a coordination complex. (From Dorland, 27th ed)	Ligand
D008956	Models, Chemical	Theoretical representations that simulate the behavior or activity of chemical processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.	Chemical Models,Chemical Model,Model, Chemical
D009211	Myoglobin	A conjugated protein which is the oxygen-transporting pigment of muscle. It is made up of one globin polypeptide chain and one heme group.
D010100	Oxygen	An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration.	Dioxygen,Oxygen-16,Oxygen 16
D011994	Recombinant Proteins	Proteins prepared by recombinant DNA technology.	Biosynthetic Protein,Biosynthetic Proteins,DNA Recombinant Proteins,Recombinant Protein,Proteins, Biosynthetic,Proteins, Recombinant DNA,DNA Proteins, Recombinant,Protein, Biosynthetic,Protein, Recombinant,Proteins, DNA Recombinant,Proteins, Recombinant,Recombinant DNA Proteins,Recombinant Proteins, DNA
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001665	Binding Sites	The parts of a macromolecule that directly participate in its specific combination with another molecule.	Combining Site,Binding Site,Combining Sites,Site, Binding,Site, Combining,Sites, Binding,Sites, Combining
D014907	Whales	Large marine mammals of the order CETACEA. In the past, they were commercially valued for whale oil, for their flesh as human food and in ANIMAL FEED and FERTILIZERS, and for baleen. Today, there is a moratorium on most commercial whaling, as all species are either listed as endangered or threatened.	Beaked Whales,Berardius,Caperea,Dwarf Sperm Whale,Giant Bottle-Nosed Whales,Goose-Beaked Whale,Gray Whale,Mesoplodon,Narwhals,Pygmy Right Whale,Pygmy Sperm Whale,Right Whale, North Atlantic,Right Whale, Southern,Ziphiidae,Ziphius,Eschrichtius robustus,Eubalaena australis,Grey Whale,Monodon monoceros,North Atlantic Right Whale,Beaked Whale,Bottle-Nosed Whale, Giant,Bottle-Nosed Whales, Giant,Dwarf Sperm Whales,Giant Bottle Nosed Whales,Giant Bottle-Nosed Whale,Goose Beaked Whale,Goose-Beaked Whales,Gray Whales,Grey Whales,Narwhal,Pygmy Right Whales,Pygmy Sperm Whales,Right Whale, Pygmy,Right Whales, Pygmy,Right Whales, Southern,Southern Right Whale,Southern Right Whales,Sperm Whale, Dwarf,Sperm Whale, Pygmy,Sperm Whales, Dwarf,Sperm Whales, Pygmy,Whale,Whale, Grey,Whale, Southern Right,Whales, Grey,Whales, Southern Right
D014978	Xenon	A noble gas with the atomic symbol Xe, atomic number 54, and atomic weight 131.30. It is found in the earth's atmosphere and has been used as an anesthetic.
D016297	Mutagenesis, Site-Directed	Genetically engineered MUTAGENESIS at a specific site in the DNA molecule that introduces a base substitution, or an insertion or deletion.	Mutagenesis, Oligonucleotide-Directed,Mutagenesis, Site-Specific,Oligonucleotide-Directed Mutagenesis,Site-Directed Mutagenesis,Site-Specific Mutagenesis,Mutageneses, Oligonucleotide-Directed,Mutageneses, Site-Directed,Mutageneses, Site-Specific,Mutagenesis, Oligonucleotide Directed,Mutagenesis, Site Directed,Mutagenesis, Site Specific,Oligonucleotide Directed Mutagenesis,Oligonucleotide-Directed Mutageneses,Site Directed Mutagenesis,Site Specific Mutagenesis,Site-Directed Mutageneses,Site-Specific Mutageneses