An atomic-scale model of a virus that infects the Salmonella bacterium. Credit: C. Hryc and the Chiu Lab, Baylor College of Medicine.
This sphere could be a prototype design for the 2018 World Cup official match soccer ball, but you won’t see it dribbled around any soccer fields. The image is actually an atomic-scale model of a virus that infects the Salmonella bacterium. Like a soccer ball, both are approximately spherical shapes created by a combination of hexagonal (six-sided) and pentagonal (five-sided) units. Wah Chiu, a biochemist at Baylor College of Medicine, and his colleagues used new computational methods to construct the model from more than 20,000 cryo-electron microscopy (cryo-EM) images. Cryo-EM is a sophisticated technique that uses electron beams for visualizing frozen samples of proteins and other biological specimens.
The researchers’ model, published in a recent issue of PNAS, shows the virus’ protein shell, or capsid, that encloses the virus’ genetic material. Each color shows capsid proteins having the same interactions with their neighbors. The fine resolution allowed researchers to identify the protein interactions essential to building a stable shell. They developed a new approach to checking the accuracy and reliability of the virus model and reporting what parts are the most certain. The approach could be used to evaluate other complex biological structures, potentially leading to better quality models and new avenues for drug design and development.
This research is funded in part by NIH under grants R01GM079429, P01GM063210, P41GM103832, PN2EY016525, T15LM007093.
James D. Watson. Credit: Wikimedia Commons, Cold Spring Harbor Laboratory.
April 6 is the birthday of two Nobel Prize winners in physiology or medicine—James Watson and Edmond H. Fischer. They have also both been NIGMS-supported researchers.
In 1953, Watson and Crick created their historic model of the shape of DNA: the double helix. Credit: Cold Spring Harbor Laboratory archives.
James D. Watson, born on this day in 1928, was honored with the Nobel Prize in 1962. He shared it with Francis H. Compton Crick and Maurice Wilkins “for their discoveries concerning the molecular structure of nucleic acids and its significance for information transfer in living material.” This laid the groundwork for future discoveries. In the early 1950s, Wilkins and another scientist, Rosalind Franklin, worked to determine DNA’s structure. In 1953, Watson and Crick discovered its shape as a double helix. This twisted ladder structure enabled other researchers to unlock the secret of how genetic information is stored, transferred and copied. Franklin is widely recognized as having played a significant role in revealing the physical structure of DNA; due to her death at age 37 in 1958, Franklin did not earn a share of the prize. Read more about DNA. Continue reading
Another cool fact about Pi: The mirror reflection of the numbers 3 1 4 spells out P I E.
Why do math lovers around the world call March 14 “Pi Day”? Because Pi, the ratio of a circle’s circumference to its diameter, is 3.14. Pi is a Greek letter (π) that represents a constant in math: All circles have the same Pi, regardless of their size. Pi has been calculated out to as many as 1 trillion digits past the decimal, and it can continue forever without repetition or pattern.
In honor of Pi Day, we asked several biomedical researchers in the field of computational biology to tell us why they love math and how they use it in their research. Continue reading