IUCr Newsletter - Volume 24, Number 4 - 10
Inorganic materials and industry minerals
The African continent is rich in raw materials critical to modern civilization including minerals, metals, diamonds and phosphates. However, large parts of the value added manufacturing
chains for these materials are currently situated outside Africa.
For a sustainable economic development of the continent, larger
parts of these chains must be relocated to Africa, and the crossborder cooperation improved. This is where crystallography and
the crystallographic community can be of help. This session combined many aspects of the study of structures, size effects, functionalities and applications of inorganic materials. The keynote
lecture "Ordered inorganic materials as templates for advanced
functional nanostructures" delivered by Robert Mokaya (UK),
revealed how to create new functional materials on the nanometer scale by manipulating suitable precursor structures. Michele Zema (Italy) described very intricate ordering phenomena
in "Coltan: a mineral family with unusual crystal chemistry."
Donald Tschuifon's (Cameroon) described the "Growth of ZnO
nanotube arrays by hydrothermal methods on ZnO film coated
Si substrates." Lahcen El Ammari (Morocco) gave a broad overview of the structures of phosphates and vanadates. Wulf Depmeier (Germany) reviewed the amusing scientific history of a
potentially economically important Li-mineral (jadarite) and
then went on to describe the structure of denisovite: "A fibrous,
nano-crystalline, polytypic, disordered mineral", that he studied
by electron crystallography and X-ray powder diffraction. Jeremie Muswema (DR Congo) discussed "Gamma rays induced
synthesis of supermagnetic Fe3O4 nanoparticles." Márcia Carvalho de Abreu Fantini (Brazil), President of the Latin American
Crystallography Association, described "Mesoporous zirconia
based materials for catalysis and SOFCs."
Wulf Depmeier and Lahcen El Ammari, Co-chairs
Inorganic Materials and Industrial Minerals Chairs and Speakers.
Crystallography for life sciences
Co-chair Alejandro Buschiazzo (Uruguay) began the session
on "Crystallography for life sciences" with a comprehensive history of the field from Dorothy Hodgkin's insulin through viruses,
with emphasis on molecular interactions dependent on sequence
and fold and the evolution of conformational change in kinases.
He noted that early ideas about one gene - one protein and one
sequence - one structure were oversimplifications and that amyloids reveal that even a single sequence can have different 3D
structures. Heini Dir (South Africa) described multifunctional
superfamily of proteins as molecular machines and stressed how
much can be learned by examining a structure under dozens of
conditions. He discussed his determination of the first protein
structure completed by an African Crystallographer. Elsie Yekwa
(France) gave an excellent presentation of her studies of inhibitors of African arenavirus nucleases. She cloned, expressed and
determined the structures of four proteins, and identified metal
ions critical to the structure of a drug target. Co-chair Mino
Caira (South Africa) described drug design using crystal structures of drugs and their protein targets. He discussed relative stabilities and solubility of polymorphs of a drug candidate and how
to design drugs that are the most potent, selective, and soluble.
Cyclodextrins have been used to deliver drugs and hormones, including steroids, and Caira determined the structure of estradiol
in a cyclodextrin. Bryan Sewell (South Africa) spoke of molecular evolution of amidases and industrial applications for nitrate
production. One of his students from Kenya soaked 100 compounds into an amidase. His results raise questions about a popular theory about the design of antmalarial drugs. Eric Chabrierè
(France) has determined the structure of a thermo stable protein
from Vesuvio hot springs that has two catalytic activities and degrades insecticides and nerve gas. Details of the two mechanisms
and the basis for stability revealed by X-ray analysis are being
used to engineer more potent agents to decontaminate nerve gas
and insecticides. Adewumi Adeyeye (South Africa) addressed tuberculosis resistance due to cell wall mycolic acid and structure
determinations of proteins in the mycolic acid synthesis pathway.
Richard Garratt (Brazil) discussed his studies of monomeric and
polymeric human septin filaments that interact with the membrane and remodel it. The only reported crystal structure of a
polymeric form is that of a hexamer composed of three types of
monomers, but the active form seems be an octamer of the four
putative different monomers. Garratt has found that homo dimers of one type seem critical to extended filament production.
Crystallography for Life Sciences Chairs and Speakers.
Co-chair Suzanna Ward surveyed the size, growth and content of the Cambridge Structural Database (CSD). On the
morning of Oct 8, 2016 it had 853,000 structures, has been
growing by 60,000 per year and 1002 were added on its biggest
day. Of these, 60% are metal organic and 75% have aromatic
rings. The top 200 pharmaceuticals are present and accounted
for. Ward noted the existence of thorough reviews concerning the use of the data to understand the structural basis for the
chemistry, properties, and functional potential of molecules. She
IUCr Newsletter ♦ Volume 24, Number 4 ♦ 2016