Atomic Movement Recorded In Real Time Through Femtosecond Electron Diffraction

Scientists at the University of Toronto were able to observe and record motions of atoms in real time. This is a huge development on the understanding chemistry and biology at the atomic level.

For the first time atomic movement as they undergo chemical transformation has been directly recorded through a process called electron diffraction. As the atoms convert into new structures and adopt new properties, scientists observed and recorded this transitional state as it happens.

For the process to work, an ultrabright femtosecond electron source is used to light up the molecular motions in the organic crystal during its transition phase. Using three key reaction coordinates within the crystal, scientists were able to reconstruct the structural evolution of its molecular system.

Combining the coordinates to make a 3D model and using Femtosecond Electron Diffraction, the duration of the transition and position of the moluecules as well as its reaction trajectory is obtained. (See video)

XPD Protein Discovered To Scan For Damaged DNA

The XPD scanner (green)is in close contact with a damaged point (red) on the DNA double helix. The damaged DNA strand lies in a deep pocket of the protein to enable a ferrous sensor (Fe) to come into contact with the damaged point, thereby halting the protein as it moves along the DNA.
Image: UZH

Xeroderma pigmentosum group D (XPD) protein, a protein associated with repairing DNA has been discovered to also scan for damaged DNA.

Deoxyribonucleic acid (DNA) is a molecule that contains genetic code or instructions used for the development and function of living organisms. DNA encodes its genetic information through the sequence of four nucleotides (guanine(G), adenine(A), thymine(T), and cytosine(C)).

Whenever DNA is damaged through ultra-violet light, cigarette smoke, toxic fumes, toxins, X-rays and radiation, and metabolic processes, it is repaired by proteins and enzymes such as Superoxide dismutases and methyl guanine methyl transferase (MGMT). Roles of these proteins and enzymes vary from recognizing damage, to correcting the damaged portions or remove them.

Unrecognized damage which does not get repaired, accelerates aging and causes cancer and genetic disorders. There are DNA disorders that involve the body having difficulty repairing DNA. Xeroderma pigmentosum (XP) and Trichothiodystrophy (TTD) are two of these disorders.

A team headed by veterinary pharmacologist and toxicologist Hanspeter Nägeli has now discovered that the protein XPD plays a key role in locating damaged DNA.