title: Detection of myoglobin desaturation in Mirounga angustirostris during apnea.
abstract: 1H NMR solution-state study of elephant seal (Mirounga angustirostris) myoglobin (Mb) and hemoglobin (Hb) establishes the temperature-dependent chemical shifts of the proximal histidyl N(delta)H signal, which reflects the respective intracellular and vascular PO2 in vivo. Both proteins exist predominantly in one major isoform and do not exhibit any conformational heterogeneity. The Mb and Hb signals are detectable in M. angustirostris tissue in vivo. During eupnea M. angustirostris muscle maintains a well-saturated MbO2. However, during apnea, the deoxymyoglobin proximal histidyl N(delta)H signal becomes visible, reflecting a declining tissue PO2. The study establishes a firm methodological basis for using NMR to investigate the metabolic responses during sleep apnea of the elephant seal and to secure insights into oxygen regulation in diving mammals.
authors.affiliation: Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla 92093-0204, California, USA.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Ponganis
authors.forename: Ulrike
authors.initials: U
authors.lastname: Kreutzer
authors.forename: Napapon
authors.initials: N
authors.lastname: Sailasuta
authors.forename: Torre
authors.initials: T
authors.lastname: Knower
authors.forename: Ralph
authors.initials: R
authors.lastname: Hurd
authors.forename: Thomas
authors.initials: T
authors.lastname: Jue
mesh_terms: D000818:Animals; D001049:Apnea / Q000378:metabolism*; D004242:Diving / Q000502:physiology; D000860:Hypoxia / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D009211:Myoglobin / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism; D010108:Oxyhemoglobins / Q000378:metabolism; D011522:Protons; D046048:Seals, Earless / Q000502:physiology*
chemical_list: D009211:Myoglobin; D010108:Oxyhemoglobins; D011522:Protons; D010100:Oxygen