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Manacá Beamline

MANACÁ (MAcromolecular micro and NAnoCrystAllography ) will be the first macromolecular crystallography beamline of Sirius and will be optimized for micrometric and sub-micrometric focus. The project includes two experimental stations, also including beams with dimensions of 0.5×0.5 micrometers (nano station) and 10×7 to 100×80 micrometers (micro station), dedicated to the study of three-dimensional structures of macromolecules, particularly complex arrangements such as viruses, membrane proteins and protein complexes and ligands.

The determination of the three-dimensional structures of proteins, with detail of the spatial positions and interactions between the atoms of these molecules, in the research area known as structural biology, is extremely important for the understanding of biological processes such as cancer, heart disease, viral diseases, tuberculosis, AIDS and others. The details at the atomic level of the structure of human proteins, and those of pathogens such as viruses and bacteria, guides the development of molecules that act as inhibitors, which can lead to the production of increasingly efficient drugs with fewer side effects.

Detailed information on the structures are important not only in health but also in the discovery of enzymes (proteins with catalytic functions) with commercial applications in food production, bio-fuels, agricultural pesticides and cosmetics.

Currently, over the 120 thousand protein structures are known with information available in the PDB database (rcsb.org), but some of the most challenging types, such as proteins located in the lipid membranes of cells, which constitute about 30% of proteins of eukaryotic organisms, are not throughly explored. The main challenge is to produce crystals of these molecules, a necessary step in determining the structure using X-ray crystallography. The crystals which are produced often have dimensions of a few microns and are quite fragile, limiting the acquisition of data in the traditional manner.

Proteins that act in the form of complexes, which can be composed of several proteins and nucleic acids, such as the ribosome, are also challenging, and new data collection strategies have been developed and will be included in the experimental stations of the MANACÁ beamline.

The use of synchrotron radiation beam with micrometric focus on protein crystallography is becoming the preferred choice for the study of micro-crystals of membrane proteins and complexes of proteins that are large, flexible and of difficult crystallization. Even in experiments with larger crystals, the fine beam allows the analysis of the whole area of the crystal and the identification of more uniform and ordered regions that result in data with higher resolution and quality.

CONTACT & STAFF

Facility Tel.: +55 19 3517 5170
Facility E-mail: manaca@lnls.br

Coordination: Ana C. de M. Zeri
Tel.: +55 19 3518 2948
E-mail: ana.zeri@lnls.br

Click here  for more information on this Facility team.

EXPERIMENTAL TECHNIQUES

The experimental station with microfocus will have a beam that can be manipulated with the help of optical openings to obtain beams of  10×7 to 100×80 micrometers. The beam at this station will be used as a secondary source for the nanofocus station, where the x-ray beam will have dimensions of 0.5×0.5 microns. Data collection strategies in serial mode using micro-crystals deposited in micro-grids or chips, and rastering acquisition will be employed in the microfocus experimental station and new techniques such as micro-jets of lipids and acoustic suspension drops containing micro-crystals will be implemented in nanofocus station.

The use of a beam of micrometric dimensions reduces the damage caused by radiation to fragile micro-crystals of proteins. However, the divergence of the beam must remain below the mosaicity of any crystal of interest. Because of that, the divergence of the beam at the focus should remain below 0.5 mrad. This difference allows diffraction peaks of crystals with unit cell of up to 1000 Å to be resolved, depending on the experimental collection strategies.

Thanks to the high brightness of Sirius, in the energy range around 12 keV, in which most experiments will be made, the estimated flux of MANACÁ beamline will be 1013 ph/s. And similarly to the CARNAÚBA and EMA beamlines, this beamline will also cover a wide range of energies, coming close to the K edge of sulfur. In principle, since most native proteins contain sulfur atoms (in methionine and cysteine), single wavelength anomalous diffraction (SAD) techniques with sulfur offers the possibility of a direct determination of structure. In addition to all the infrastructure for preparation and conditioning of protein crystals, the microfocus experimental station will be equipped with a kappa goniometer that allows the better alignment of crystals and different crystallographic orientations, making it possible to obtain high-resolution sampling in certain experimental conditions.

LAYOUT

PARAMETERS

Parameter Value Condition
Energy range 5 – 20 keV
Energy resolution (ΔE/E) 10-4
Harmonic content <10-4
Energy scan Yes
Beam size 0.5×0.5 μm
10×7 to 100×80 μm
nano station
micro station
Beam divergence < 0.5 mrad