Laboratory of Molecular Biology

About: Laboratory of Molecular Biology is a facility organization based out in Cambridge, Cambridgeshire, United Kingdom. It is known for research contribution in the topics: Gene & RNA. The organization has 19395 authors who have published 24236 publications receiving 2101480 citations.

Structure of gelsolin segment 1-actin complex and the mechanism of filament severing

Abstract: The structure of the segment 1 domain of gelsolin, a protein that fragments actin filaments in cells, is reported in complex with actin. Segment 1 binds monomer using an apolar patch rimmed by hydrogen bonds in a cleft between actin domains. On the actin filament model it binds tangentially, disrupting only those contacts between adjacent subunits in one helical strand. The segment 1 fold is general for all segments of the gelsolin family because the conserved residues form the core of the structure. It also provides a basis for understanding the origin of an amyloidosis caused by a gelsolin variant.

Sustained translational repression by eIF2α-P mediates prion neurodegeneration

Abstract: Accumulation of prion protein during prion replication causes persistent translational repression of global protein synthesis, which is mediated by eIF2α-P and is associated with synaptic failure and neuronal loss in prion-diseased mice; promoting translational recovery in hippocampi of prion-infected mice is neuroprotective. Despite extensive research, the mechanisms leading to neuronal loss in neurodegenerative disease are still little understood, and no treatments or promising treatment strategies exist. Using prion-diseased mice as a model, this study demonstrates that the accumulation of misfolded prion protein during prion replication causes persistent translational repression of global protein synthesis. This is mediated by eIF2α-P and is associated with synaptic failure and neuronal loss in prion-diseased mice. Promoting translational recovery in the hippocampi of prion-infected mice is neuroprotective, suggesting that a generic approach involving the fine-tuning of protein synthesis may be worth pursuing in prion diseases, and perhaps in other neurodegenerative disorders involving protein misfolding. The mechanisms leading to neuronal death in neurodegenerative disease are poorly understood. Many of these disorders, including Alzheimer’s, Parkinson’s and prion diseases, are associated with the accumulation of misfolded disease-specific proteins. The unfolded protein response is a protective cellular mechanism triggered by rising levels of misfolded proteins. One arm of this pathway results in the transient shutdown of protein translation, through phosphorylation of the α-subunit of eukaryotic translation initiation factor, eIF2. Activation of the unfolded protein response and/or increased eIF2α-P levels are seen in patients with Alzheimer’s, Parkinson’s and prion diseases1,2,3,4, but how this links to neurodegeneration is unknown. Here we show that accumulation of prion protein during prion replication causes persistent translational repression of global protein synthesis by eIF2α-P, associated with synaptic failure and neuronal loss in prion-diseased mice. Further, we show that promoting translational recovery in hippocampi of prion-infected mice is neuroprotective. Overexpression of GADD34, a specific eIF2α-P phosphatase, as well as reduction of levels of prion protein by lentivirally mediated RNA interference, reduced eIF2α-P levels. As a result, both approaches restored vital translation rates during prion disease, rescuing synaptic deficits and neuronal loss, thereby significantly increasing survival. In contrast, salubrinal, an inhibitor of eIF2α-P dephosphorylation5, increased eIF2α-P levels, exacerbating neurotoxicity and significantly reducing survival in prion-diseased mice. Given the prevalence of protein misfolding and activation of the unfolded protein response in several neurodegenerative diseases, our results suggest that manipulation of common pathways such as translational control, rather than disease-specific approaches, may lead to new therapies preventing synaptic failure and neuronal loss across the spectrum of these disorders.

Mechanisms of Cooperativity and Allosteric Regulation in Proteins

Abstract: Preface 1. Introduction 2. Haemoglobin: Dependence of allosteric equilibrium on spin state and coordination of the haem iron 3. Haemocyanin: Dependence of allosteric equilibrium on coordination and valency of a binuclear copper complex 4. Haemerythrin: Cooperativity in a binuclear iron complex 5. Glycogen phosphorylase: Control of glycolysis 6. Phosphofructokinase: Further control of glycolysis 7. Feedback inhibition of a biosynthetic pathway: Aspartate Transcarbamoylase 8. Control of nitrogen metabolism: Glutamine synthetase 9. Cooperativity and feedback inhibition without change of quaternary structure: The "trp" and "met" repressors of E. Coli 10. Immunoglobulins: Cooperative binding to multivalent antigens 11. Allosteric membrane proteins.

Genetically encoding N|[epsi]|-acetyllysine in recombinant proteins

Abstract: N(epsilon)-acetylation of lysine (1) is a reversible post-translational modification with a regulatory role that rivals that of phosphorylation in eukaryotes. No general methods exist to synthesize proteins containing N(epsilon)-acetyllysine (2) at defined sites. Here we demonstrate the site-specific incorporation of N(epsilon)-acetyllysine in recombinant proteins produced in Escherichia coli via the evolution of an orthogonal N(epsilon)-acetyllysyl-tRNA synthetase/tRNA(CUA) pair. This strategy should find wide applications in defining the cellular role of this modification.

Structure of the Yeast Mitochondrial Large Ribosomal Subunit

Abstract: Mitochondria have specialized ribosomes that have diverged from their bacterial and cytoplasmic counterparts. We have solved the structure of the yeast mitoribosomal large subunit using single-particle cryo-electron microscopy. The resolution of 3.2 angstroms enabled a nearly complete atomic model to be built de novo and refined, including 39 proteins, 13 of which are unique to mitochondria, as well as expansion segments of mitoribosomal RNA. The structure reveals a new exit tunnel path and architecture, unique elements of the E site, and a putative membrane docking site.