| 1. |
- Apostolov, Rossen, et al.
(författare)
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Membrane attachment facilitates ligand access to the active site in monoamine oxidase A
- 2009
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Ingår i: Biochemistry. - : American Chemical Society (ACS). - 0006-2960 .- 1520-4995. ; 48:25, s. 5864-5873
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Tidskriftsartikel (refereegranskat)abstract
- Monoamine oxidase membrane enzymes are responsible for the catalytic breakdown of extra- and intracellular neurotransmitters and are targets for the development of central nervous system drugs. We analyzed the dynamics of rat MAOA by performing multiple independent molecular dynamics simulations of membrane-bound and membrane-free forms to clarify the relationship between the mechanics of the enzyme and its function, with particular emphasis on the significance of membrane attachment. Principal component analysis of the simulation trajectories as well as correlations in the fluctuations of the residues pointed to the existence of three domains that define the global dynamics of the protein. Interdomain anticorrelated movements in the membrane-bound system facilitated the relaxation of interactions between residues surrounding the substrate cavity and induced conformational changes which expanded the active site cavity and opened putative pathways for substrate uptake and product release. Such events were less pronounced in the membrane-free system due to differences in the nature of the dominant modes of motion. The presence of the lipid environment is suggested to assist in decoupling the interdomain motions, consistent with the observed reduction in enzyme activity under membrane-free conditions. Our results are also in accordance with mutational analysis which shows that modifications of interdomain hinge residues decrease the activity of rat MAOA in solution.
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| 2. |
- Kikugawa, Gota, et al.
(författare)
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Application of MDGRAPE-3, a Special Purpose Board for Molecular Dynamics Simulations, to Periodic Biomolecular Systems
- 2009
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Ingår i: Journal of Computational Chemistry. - : Wiley. - 0192-8651 .- 1096-987X. ; 30:1, s. 110-118
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Tidskriftsartikel (refereegranskat)abstract
- We describe the application of a special purpose board for molecular dynamics simulations, named MDGRAPE-3, to the problem of simulating periodic bio-molecular systems. MDGRAPE-3 is the latest board in a series of hardware accelerators designed to calculate the nonbonding long-range interactions much more rapidly than normal processors. So far, MDGRAPEs were mainly applied to isolated systems, where very many nonbonded interactions were calculated without any distance cutoff. However, in order to regulate the density and pressure during simulations of membrane embedded protein systems, one has to evaluate interactions under periodic boundary conditions. For this purpose, we implemented the Particle-Mesh Ewald (PME) method, and its approximation with distance cutoffs and charge neutrality as proposed by Wolf et al., using MDGRAPE-3. When the two methods were applied to simulations of two periodic biomolecular systems, a single MDGRAPE-3 achieved 30-40 times faster computation times than a single conventional processor did in the both cases. Both methods are shown to have the same molecular structures and dynamics of the systems.
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| 3. |
- Moretti, Rocco, et al.
(författare)
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Community-wide evaluation of methods for predicting the effect of mutations on protein-protein interactions
- 2013
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Ingår i: Proteins. - : Wiley. - 0887-3585 .- 1097-0134. ; 81:11, s. 1980-1987
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Tidskriftsartikel (refereegranskat)abstract
- Community-wide blind prediction experiments such as CAPRI and CASP provide an objective measure of the current state of predictive methodology. Here we describe a community-wide assessment of methods to predict the effects of mutations on protein-protein interactions. Twenty-two groups predicted the effects of comprehensive saturation mutagenesis for two designed influenza hemagglutinin binders and the results were compared with experimental yeast display enrichment data obtained using deep sequencing. The most successful methods explicitly considered the effects of mutation on monomer stability in addition to binding affinity, carried out explicit side-chain sampling and backbone relaxation, evaluated packing, electrostatic, and solvation effects, and correctly identified around a third of the beneficial mutations. Much room for improvement remains for even the best techniques, and large-scale fitness landscapes should continue to provide an excellent test bed for continued evaluation of both existing and new prediction methodologies. Proteins 2013; 81:1980-1987.
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