Diving into the heart of the molecules of life

Taking atomic snapshots is very important to biologists who want to understand the architecture of the macromolecules that make up our cells. However, these nano-objects are far too small to be observed with a microscope. This is why other methods such as X-ray crystallography are needed to provide accurate images at an atomic scale. This film, Diving into the heart of the molecules of life, follows the different steps of a crystallographic study and describes the work of researchers at CNRS (ARN Laboratory, Institut de Biologie Moléculaire et Cellulaire, Strasbourg), from the purification of a macromolecule from living cells, its crystallisation and the analysis of the crystals using synchrotron radiation, to the assembly of a three-dimensional image. This movie covers several aspects of scientists' work which are not widely known: the cloning of biomolecules, the use of large instruments such as synchrotron X-ray sources, and 3D visualisation.

Category: Education. Duration: 13m 26s

 License: Creative Commons

Sir Lawrence Bragg on crystals and gems

A series of six outside broadcasts filmed at the Royal Institution in the late 1950s and early 1960s, The Nature of Things was presented by William Lawrence Bragg with the assistance of Bill Coates. This is an extract from Crystals and Gems, the last show in the first series, exploring the properties and molecular structure of crystals.

Coates recalled Bragg once remarking to him: "never talk about science, show it to them", which is what The Nature of Things set out to do. Like the Christmas Lectures, the programmes were structured around a series of demonstrations and were filmed as a lecture in the Ri's theatre. Although the filming took place with an audience of adults, the series was aimed at children and broadcast on children's television. As he states at the end of the series, he hoped it would provoke "deep interest in the science of everyday things".

Broadcast on BBC Television in 1959. Duration: 17m 22s
© The Royal Institution. Credits: The Royal Institution /BBC

The Mystery of the Giant Crystals

The Cave of the Crystals (Cueva de los Cristales) in the Naica Mine, Chihuahua, Mexico, houses some of the largest natural crystals ever found. They are selenite, a form of the mineral gypsum (CaSO₄.2H₂O). Juan Manuel Garcíia Ruiz and his colleagues investigate the conditions under which these huge crystals have grown over the course of thousands of years. The temperatures in the subterranean caverns are over 50°C, and the caves are filled with water containing a variety of minerals leached from the surrounding rocks.

Duration: 50m 53s

© 2014 Trianatech.com - All rights reserved

El Misterio de los Cristales Gigantes

La Cueva de los Cristales en la mina de Naica, Chihuahua, México, alberga algunos de los más grandes cristales naturales que se han encontrado. Son selenito, una forma del yeso mineral (CaSO₄.2H₂O). Juan Manuel García Ruiz y sus colegas investigan las condiciones en que estos enormes cristales han crecido a lo largo de miles de años. Las temperaturas en las cavernas subterráneas son más de 50° C, y las cuevas están llenas de agua que contiene una variedad de minerales lixiviados de las rocas circundantes.

Duration: 50m 54s

© 2014 Trianatech.com - All rights reserved

Il Mistero dei Cristalli Giganti

La Grotta dei Cristalli (Cueva de los Cristales) nella miniera di Naica, Chihuahua, Messico, ospita alcuni dei più grandi cristalli naturali mai trovati. Si tratta di cristalli di selenite, una particolare forma di gesso (CaSO₄.2H₂O). Juan Manuel García Ruiz e i suoi colleghi indagano sulle condizioni in cui questi enormi cristalli sono cresciuti nel corso di migliaia di anni. La temperatura nelle caverne sotterranee è oltre 50° C, e le grotte sono riempite con acqua contenente una varietà di minerali lisciviati dalle rocce circostanti.

Duration: 50m 58s

© 2014 Trianatech.com - All rights reserved

Le Mystère des Cristaux Géants

La Grotte des Cristaux (Cueva de los Cristales) dans la mine de Naica, Chihuahua, Mexique, abrite quelques-uns des plus grands cristaux naturels jamais trouvés. Ils sont sélénite, une forme de gypse minéral (CaSO₄.2H₂O). Juan Manuel García Ruiz et ses collègues enquêtent sur les conditions dans lesquelles ces énormes cristaux ont grandi au cours de milliers d'années. Les températures dans les cavernes souterraines sont plus de 50° C, et les grottes sont remplis avec de l'eau contenant une variété de minéraux lessivés des roches environnantes.

Duration: 50m 58s

© 2014 Trianatech.com - All rights reserved

Celebrating the International Year of Crystallography with methylation of Nod Factor

Each year, ~150 million tonnes of atmospheric nitrogen are converted to plant nutrients (eliminating the load of artificial fertilizers) by soil bacteria, called rhizobia, that live in symbiosis with legume plants, such as lupine. The association is highly specific and before it starts, the symbionts must recognize each other via exchange of precise chemical signals. The plant's root produces characteristic flavonoids, while the bacterial 'business card', called nodulation factor (NF), is an oligosaccharide molecule with a unique pattern of strange chemical decorations. The nodulation factor is named very adequately: once recognized, it will induce formation of root nodules, to be colonized by the bacterial partner. Rhizobia have unique biosynthetic pathways to produce NF, involving about a dozen of specialized proteins. One of them is NodS, an enzyme that decorates the Nod factor with a methyl group (CH3), transferred from a donor molecule called SAM. Dr. Ozgur Cakici, working at the Center for Biocrystallographic Research in Poznan (Poland), discovered the crystal structure of NodS and was able to elucidate its enzymatic mechanism, so elegantly shown in the movie. The enzyme starts with an open conformation, which allows docking of the SAM molecule. Upon SAM binding, the protein conformation changes dramatically, burying the donor molecule and forming a docking platform for the NF acceptor. When the NF molecule completes the tripartite complex, the methyl group gets transferred, and the products can depart the enzyme. The last component to leave is SAH, a molecule generated from SAM by methyl group removal. The open NodS molecule is ready to start a new catalytic cycle.

To solve the structure of NodS and of its complex with SAH, Ozgur first genetically modified bacterial cells for production of the protein in a variant containing selenium (Se) atoms. Crystals of that protein were taken for diffraction experiments to a synchrotron center that provided an extremely powerful X-ray beam with tunable wavelength. The experimental data were the basis for structure determination, which utilized the method of multiwavelength anomalous diffraction (MAD).

Dr. Cakici's results were published in Acta Crystallographica (Acta Cryst. F64, 1149-1152, 2008) and in the Journal of Molecular Biology (J. Mol. Biol. 404, 874-889, 2010).

Duration: 1m 58s
© Center for Biocrystallographic Research, Poznan

Sir Lawrence Bragg on crystals and gems

A series of six outside broadcasts filmed at the Royal Institution in the late 1950s and early 1960s, The Nature of Things was presented by William Lawrence Bragg with the assistance of Bill Coates. This is an extract from Crystals and Gems, the last show in the first series, exploring the properties and molecular structure of crystals.

Coates recalled Bragg once remarking to him: "never talk about science, show it to them", which is what The Nature of Things set out to do. Like the Christmas Lectures, the programmes were structured around a series of demonstrations and were filmed as a lecture in the Ri's theatre. Although the filming took place with an audience of adults, the series was aimed at children and broadcast on children's television. As he states at the end of the series, he hoped it would provoke "deep interest in the science of everyday things".

Broadcast on BBC Television in 1959. Duration: 17m 22s
© The Royal Institution. Credits: The Royal Institution /BBC