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Hungerford, United Kingdom

Moraes I.,Imperial College London | Moraes I.,Diamond Light Source | Moraes I.,Rutherford Appleton Laboratory | Evans G.,Diamond Light Source | And 4 more authors.
Biochimica et Biophysica Acta - Biomembranes | Year: 2014

The field of Membrane Protein Structural Biology has grown significantly since its first landmark in 1985 with the first three-dimensional atomic resolution structure of a membrane protein. Nearly twenty-six years later, the crystal structure of the beta2 adrenergic receptor in complex with G protein has contributed to another landmark in the field leading to the 2012 Nobel Prize in Chemistry. At present, more than 350 unique membrane protein structures solved by X-ray crystallography (http://blanco.biomol.uci.edu/mpstruc/exp/list, Stephen White Lab at UC Irvine) are available in the Protein Data Bank. The advent of genomics and proteomics initiatives combined with high-throughput technologies, such as automation, miniaturization, integration and third-generation synchrotrons, has enhanced membrane protein structure determination rate. X-ray crystallography is still the only method capable of providing detailed information on how ligands, cofactors, and ions interact with proteins, and is therefore a powerful tool in biochemistry and drug discovery. Yet the growth of membrane protein crystals suitable for X-ray diffraction studies amazingly remains a fine art and a major bottleneck in the field. It is often necessary to apply as many innovative approaches as possible. In this review we draw attention to the latest methods and strategies for the production of suitable crystals for membrane protein structure determination. In addition we also highlight the impact that third-generation synchrotron radiation has made in the field, summarizing the latest strategies used at synchrotron beamlines for screening and data collection from such demanding crystals. This article is part of a Special Issue entitled: Structural and biophysical characterisation of membrane protein-ligand binding. © 2013 The Authors. Source


Abuhammad A.,University of Oxford | Abuhammad A.,University of Jordan | Lowe E.D.,University of Oxford | Mcdonough M.A.,University of Oxford | And 5 more authors.
Acta Crystallographica Section D: Biological Crystallography | Year: 2013

Arylamine N-acetyltransferase from Mycobacterium tuberculosis (TBNAT) plays an important role in the intracellular survival of the microorganism inside macrophages. Medicinal chemistry efforts to optimize inhibitors of the TBNAT enzyme have been hampered by the lack of a three-dimensional structure of the enzyme. In this paper, the first structure of TBNAT, determined using a lone crystal produced using cross-seeding with the homologous protein from M. marinum, is reported. Despite the similarity between the two enzymes (74% sequence identity), they show distinct physical and biochemical characteristics. The structure elegantly reveals the characteristic features of the protein surface as well as details of the active site of TBNAT relevant to drug-discovery efforts. The crystallographic analysis of the diffraction data presented many challenges, since the crystal was twinned and the habit possessed pseudo-translational symmetry. © 2013 International Union of Crystallography. Source


Shaw Stewart P.D.,Douglas Instruments | Kolek S.A.,Douglas Instruments | Briggs R.A.,Douglas Instruments | Chayen N.E.,Imperial College London | Baldock P.F.M.,Douglas Instruments
Crystal Growth and Design | Year: 2011

Microseed matrix-screening combined with random screens (rMMS) is a significant recent breakthrough in protein crystallization. In this study, a very reproducible assay for crystal seeds was set up that allowed the following recommendations to be made: (1) the suitability of a solution for suspending seed crystals can be predicted by incubating (uncrushed) crystals in it for one day and observing crystal stability. (2) For routine rMMS, seed crystals should be suspended in the crystallization cocktail that gave the original crystals. (3) Seed crystals can be suspended in PEG or NaCl solutions to reduce the prevalence of salt crystals. (4) Protein complexes can be seeded with seed crystals suspended in PEG. If necessary, seed crystals can also be suspended in the original crystallization cocktail with any individual ingredients that destabilize the complex removed. (5) "Preseeding" of the protein stock should not be used if rMMS is available, because it is less effective. (6) Seed crystals can be harvested from microfluidic devices. (7) Heterogeneous nucleants and cross-seeding are less effective than rMMS, but they can be used if seed crystals cannot be obtained. A theoretical case and practical suggestions are also put forward for producing crystals with different space groups. © 2011 American Chemical Society. Source

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