RESUMEN
The adenine nucleotide translocase (ANT) of the mitochondrial inner membrane exchanges ADP for ATP. Mitochondria were isolated from human vastus lateralis muscle (nâ¯=â¯9). Carboxyatractyloside titration of O2 consumption rate (Jo) at clamped [ADP] of 21⯵M gave ANT abundance of 0.97⯱â¯0.14â¯nmol ANT/mg and a flux control coefficient of 82%⯱â¯6%. Flux control fell to 1%⯱â¯1% at saturating (2â¯mM) [ADP]. The KmADP for Jo was 32.4⯱â¯1.8⯵M. In terms of the free (-3) ADP anion this KmADP was 12.0⯱â¯0.7⯵M. A novel luciferase-based assay for ATP production gave KmADP of 13.1⯱â¯1.9 µM in the absence of ATP competition. The free anion KmADP in this case was 2.0⯱â¯0.3⯵M. Targeted proteomic analyses showed significant acetylation of ANT Lysine23 and that ANT1 was the most abundant isoform. Acetylation of Lysine23 correlated positively with KmADP, râ¯=â¯0.74, Pâ¯=â¯0.022. The findings underscore the central role played by ANT in the control of oxidative phosphorylation, particularly at the energy phosphate levels associated with low ATP demand. As predicted by molecular dynamic modeling, ANT Lysine23 acetylation decreased the apparent affinity of ADP for ANT binding.
Asunto(s)
Translocador 1 del Nucleótido Adenina/metabolismo , Metabolismo Energético , Lisina/metabolismo , Mitocondrias Musculares/metabolismo , Acetilación , Adenosina Difosfato/metabolismo , Adenosina Trifosfato/metabolismo , Adulto , Femenino , Humanos , Masculino , Músculo Esquelético/metabolismo , Fosforilación Oxidativa , Consumo de OxígenoRESUMEN
The reported data describe the crystallization, crystal packing, structure determination and twinning of the unliganded Fab (antigen-binding fragment) from the NISTmAb (standard reference material 8671). The raw atomic coordinates are available as Protein Data Bank structure 5K8A and biological aspects are described in the article, (Karageorgos et al., 2017) [1]. Crystal data show that the packing is unique, and show the basis for the crystal's twinned growth. Twinning is a common and often serious problem in protein structure determination by x-ray crystallography [2]. In the present case the twinning is due to a small deviation (about 0.3 nm) from 4-fold symmetry in the primary intermolecular interface. The deviation produces pseudosymmetry, generating slightly different conformations of the protein, and alternating strong and weak forms of key packing interfaces throughout the lattice.
RESUMEN
BACKGROUND: Following didactic instruction, most aircrew are able to experience some of the disorienting illusions and limitations of the orientation senses in a variety of ground-based devices. In order to reinforce instruction in spatial disorientation (SD) within the environment in which they operate, British Army Air Corps helicopter pilots also receive an airborne demonstration of the limitations of their orientation senses prior to rotary-wing instrument flight training. The objective of this assessment was to determine whether the SD demonstration sortie would be an effective adjunct in training aircrew in SD in the U.S. Army. METHODS: There were 45 aviators and training personnel who experienced the sortie and gave their opinion in questionnaires. RESULTS: The following conclusions were made: the maneuvers performed in the SD demonstration sortie, and the sortie overall, were extremely effective at demonstrating the limitations of the orientation senses; the SD sortie attracted a significantly higher rating in its effectiveness to train aviators in SD than all the currently available methods; the introduction of the sortie into the initial flight training syllabus would be a distinct enhancement to the SD training of aviators and associated personnel; and the introduction of the sortie into refresher training in field units would also be an advantage. CONCLUSION: Other services are encouraged to consider this enhancement to the SD training of aviators.