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71.
Protein deacetylation by sirtuins: delineating a post-translational regulatory program responsive to nutrient and redox stressors 总被引:1,自引:1,他引:0
Lysine acetylation/deacetylation is increasingly being recognized as common post-translational modification that appears to
be broadly operational throughout the cell. The functional roles of these modifications, outside of the nucleus, have not
been extensively studied. Moreover, as acetyl-CoA donates the acetyl group for acetylation, nutrient availability and energetic
status may be pivotal in this modification. Similarly, nutrient limitation is associated with the deacetylation reaction.
This modification is orchestrated by a novel family of sirtuin deacetylases that function in a nutrient and redox dependent
manner and targets non-histone protein deacetylation. In compartment-specific locations, candidate target proteins undergoing
lysine-residue deacetylation are being identified. Through these investigations, the functional role of this post-translational
modification is being delineated. We review the sirtuin family proteins, discuss their functional effects on target proteins,
and postulate on potential biological programs and disease processes that may be modified by sirtuin-mediated deacetylation
of target proteins. 相似文献
72.
Future steam turbines will use hollow structures so that the turbine inlet temperature can be in- creased to improve the thermal efficiency. These hollow structures are made of the nickel-base alloy Nicro- fer 6025 HT and consist of a wire mesh between two cover sheets. The cover sheets can be joined to the wire mesh by capacitor discharge welding due to its extremely short welding duration. The goal of this re- search is to investigate suitable welding parameters so that the weld spots form in an optimum way to in- crease the tensile shear strength and reduce spattering. Tensile shear tests, three-point bending tests, and micrographs were used to judge the joint quality of structures made with various welding parameters. The results show that the best welds are obtained with a transmission ratio of 1:200, welding energy of 70% to 95%, and electrode force of 7 to 9 MPa. 相似文献
73.
74.
The individual functional properties and spatial arrangement of afferent synaptic inputs on dendrites have a critical role in the processing of information by neurons in the mammalian brain. Although recent work has identified visually-evoked local dendritic calcium signals in the rodent visual cortex, sensory-evoked signalling on the level of dendritic spines, corresponding to individual afferent excitatory synapses, remains unexplored. Here we used a new variant of high-resolution two-photon imaging to detect sensory-evoked calcium transients in single dendritic spines of mouse cortical neurons in vivo. Calcium signals evoked by sound stimulation required the activation of NMDA (N-methyl-D-aspartate) receptors. Active spines are widely distributed on basal and apical dendrites and pure-tone stimulation at different frequencies revealed both narrowly and widely tuned spines. Notably, spines tuned for different frequencies were highly interspersed on the same dendrites: even neighbouring spines were mostly tuned to different frequencies. Thus, our results demonstrate that NMDA-receptor-dependent single-spine synaptic inputs to the same dendrite are highly heterogeneous. Furthermore, our study opens the way for in vivo mapping of functionally defined afferent sensory inputs with single-synapse resolution. 相似文献
75.
Nègre N Brown CD Ma L Bristow CA Miller SW Wagner U Kheradpour P Eaton ML Loriaux P Sealfon R Li Z Ishii H Spokony RF Chen J Hwang L Cheng C Auburn RP Davis MB Domanus M Shah PK Morrison CA Zieba J Suchy S Senderowicz L Victorsen A Bild NA Grundstad AJ Hanley D MacAlpine DM Mannervik M Venken K Bellen H White R Gerstein M Russell S Grossman RL Ren B Posakony JW Kellis M White KP 《Nature》2011,471(7339):527-531
76.
Ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) catalyses the fixation of atmospheric CO(2) in photosynthesis, but tends to form inactive complexes with its substrate ribulose 1,5-bisphosphate (RuBP). In plants, Rubisco is reactivated by the AAA(+) (ATPases associated with various cellular activities) protein Rubisco activase (Rca), but no such protein is known for the Rubisco of red algae. Here we identify the protein CbbX as an activase of red-type Rubisco. The 3.0-? crystal structure of unassembled CbbX from Rhodobacter sphaeroides revealed an AAA(+) protein architecture. Electron microscopy and biochemical analysis showed that ATP and RuBP must bind to convert CbbX into functionally active, hexameric rings. The CbbX ATPase is strongly stimulated by RuBP and Rubisco. Mutational analysis suggests that CbbX functions by transiently pulling the carboxy-terminal peptide of the Rubisco large subunit into the hexamer pore, resulting in the release of the inhibitory RuBP. Understanding Rubisco activation may facilitate efforts to improve CO(2) uptake and biomass production by photosynthetic organisms. 相似文献
77.
The anaerobic oxidation of methane (AOM) with sulphate, an area currently generating great interest in microbiology, is accomplished by consortia of methanotrophic archaea (ANME) and sulphate-reducing bacteria. The enzyme activating methane in methanotrophic archaea has tentatively been identified as a homologue of methyl-coenzyme M reductase (MCR) that catalyses the methane-forming step in methanogenic archaea. Here we report an X-ray structure of the 280?kDa heterohexameric ANME-1 MCR complex. It was crystallized uniquely from a protein ensemble purified from consortia of microorganisms collected with a submersible from a Black Sea mat catalysing AOM with sulphate. Crystals grown from the heterogeneous sample diffract to 2.1?? resolution and consist of a single ANME-1 MCR population, demonstrating the strong selective power of crystallization. The structure revealed ANME-1 MCR in complex with coenzyme M and coenzyme B, indicating the same substrates for MCR from methanotrophic and methanogenic archaea. Differences between the highly similar structures of ANME-1 MCR and methanogenic MCR include a F(430) modification, a cysteine-rich patch and an altered post-translational amino acid modification pattern, which may tune the enzymes for their functions in different biological contexts. 相似文献
78.
A map of the cis-regulatory sequences in the mouse genome 总被引:1,自引:0,他引:1
79.
80.
Ulrich Hoyer 《Archive for History of Exact Sciences》1974,13(4):359-375
Ohne Zusammenfassung
Vorgelegt von
M. Klein 相似文献