Biomaterial Database

Spin-lattice relaxation of denatured nitrosyl hemoproteins. 1996

E Wajnberg, and O C Alves

Centro Brasileiro de Pesquisas Físicas, Rua Xavier Sigaud, Rio de Janeiro, Brazil.

The temperature dependence of the spin-lattice relaxation of denatured nitrosyl hemoglobin (HbNO), nitrosyl myoglobin, powdered HbNO, and hematin-NO was studied between 4 and 70 K. The results were fitted with both Tn and e-delta/tau models. In the first model, the relaxation is mediated by tunneling modes of a two-level system. A correlation between the n values and the functional state of the protein was observed. The striking coincidence of the range of the low-lying energy level and the temperature range where EPR spectra change suggests the existence of two conformations of the bound heme. The importance of the presence and structure of the globin is revealed in the difference between relaxation parameters of native proteins, denatured proteins, and hematin.

UI	MeSH Term	Description	Entries
D008872	Microwaves	That portion of the electromagnetic spectrum from the UHF (ultrahigh frequency) radio waves and extending into the INFRARED RAYS frequencies.	EHF Waves,Extremely High Frequency Radio Waves,Micro Wave,Micro Waves,Ultrahigh Frequency Waves,Microwave Radiation,EHF Wave,Micro Waves,Microwave,Microwave Radiations,Radiation, Microwave,Ultrahigh Frequency Wave,Wave, EHF,Wave, Micro,Wave, Ultrahigh Frequency,Waves, Micro
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.
D009603	Nitroso Compounds	Organic compounds containing the nitroso (-N	Compounds, Nitroso
D011489	Protein Denaturation	Disruption of the non-covalent bonds and/or disulfide bonds responsible for maintaining the three-dimensional shape and activity of the native protein.	Denaturation, Protein,Denaturations, Protein,Protein Denaturations
D004578	Electron Spin Resonance Spectroscopy	A technique applicable to the wide variety of substances which exhibit paramagnetism because of the magnetic moments of unpaired electrons. The spectra are useful for detection and identification, for determination of electron structure, for study of interactions between molecules, and for measurement of nuclear spins and moments. (From McGraw-Hill Encyclopedia of Science and Technology, 7th edition) Electron nuclear double resonance (ENDOR) spectroscopy is a variant of the technique which can give enhanced resolution. Electron spin resonance analysis can now be used in vivo, including imaging applications such as MAGNETIC RESONANCE IMAGING.	ENDOR,Electron Nuclear Double Resonance,Electron Paramagnetic Resonance,Paramagnetic Resonance,Electron Spin Resonance,Paramagnetic Resonance, Electron,Resonance, Electron Paramagnetic,Resonance, Electron Spin,Resonance, Paramagnetic
D005914	Globins	A superfamily of proteins containing the globin fold which is composed of 6-8 alpha helices arranged in a characterstic HEME enclosing structure.	Globin
D006420	Hemeproteins	Proteins that contain an iron-porphyrin, or heme, prosthetic group resembling that of hemoglobin. (From Lehninger, Principles of Biochemistry, 1982, p480)	Hemeprotein,Heme Protein,Heme Proteins,Protein, Heme,Proteins, Heme
D006427	Hemin	Chloro(7,12-diethenyl-3,8,13,17-tetramethyl-21H,23H-porphine-2,18-dipropanoato(4-)-N(21),N(22),N(23),N(24)) ferrate(2-) dihydrogen.	Ferriprotoporphyrin,Hematin,Alkaline Hematin D-575,Chlorohemin,Ferrihaem,Ferriheme Chloride,Ferriprotoporphyrin IX,Ferriprotoporphyrin IX Chloride,Panhematin,Protohemin,Protohemin IX,Alkaline Hematin D 575,Chloride, Ferriheme,Chloride, Ferriprotoporphyrin IX,Hematin D-575, Alkaline
D006454	Hemoglobins	The oxygen-carrying proteins of ERYTHROCYTES. They are found in all vertebrates and some invertebrates. The number of globin subunits in the hemoglobin quaternary structure differs between species. Structures range from monomeric to a variety of multimeric arrangements.	Eryhem,Ferrous Hemoglobin,Hemoglobin,Hemoglobin, Ferrous
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man