The secret double life of histone H3 as a copper reductase enzyme

July 02, 2020

In a study that takes another look at histones' origins, researchers report these proteins, known for DNA-packing, may have evolutionary roots in early life in helping to maintain the use of metals like copper - fundamental for biological processes, but which became toxic to eukaryotes as they adapted to global oxygenation. Histone proteins are highly basic proteins ubiquitous across all forms of eukaryotic life. Like spools, they form the structures around which DNA is wound. Without histones, life's exceedingly long genomic molecules wouldn't be able to be fit inside tiny cell nuclei as chromosomes. The presence of simple histones in archaea - the ancestors of all complex cellular life - suggests ancient evolutionary roots. However, their function in these forms of life isn't well understood. Using a host of approaches ranging from in vitro biochemistry to in vivo genetic and molecular analysis, Narsis Attar and colleagues discovered a previously unknown function of the histone H3-H4 tetramer. Attar et al. identified that the H3-H4 tetramer also serves as an oxidoreductase enzyme for copper, an element essential to all life. However, in nature, copper most commonly occurs in a form toxic to oxygen-utilizing organisms. The newly found reductase activity of H3-H4 makes this harmful copper oxidation state safe for use inside cells. The results suggest histones may have originally evolved in anerobic life as a way to adapt to oxygenated environments, rather than for DNA compaction. In a related Perspective, Johannes Rudolph and Karolin Luger regard the study's findings as "potentially paradigm-shifting," particularly in respect to histone evolution and subsequent adoption in DNA compaction. "Perhaps the original role of histone proteins was to protect against oxygen toxicity in response to the increase in oxygen concentrations that allowed for the evolution of eukaryotes and multicellular organisms," write Rudolph and Luger, noting that further characterization of histone function from archaeal organisms is needed to better understand their non-genomic roles.
-end-


American Association for the Advancement of Science

Related DNA Articles from Brightsurf:

A new twist on DNA origami
A team* of scientists from ASU and Shanghai Jiao Tong University (SJTU) led by Hao Yan, ASU's Milton Glick Professor in the School of Molecular Sciences, and director of the ASU Biodesign Institute's Center for Molecular Design and Biomimetics, has just announced the creation of a new type of meta-DNA structures that will open up the fields of optoelectronics (including information storage and encryption) as well as synthetic biology.

Solving a DNA mystery
''A watched pot never boils,'' as the saying goes, but that was not the case for UC Santa Barbara researchers watching a ''pot'' of liquids formed from DNA.

Junk DNA might be really, really useful for biocomputing
When you don't understand how things work, it's not unusual to think of them as just plain old junk.

Designing DNA from scratch: Engineering the functions of micrometer-sized DNA droplets
Scientists at Tokyo Institute of Technology (Tokyo Tech) have constructed ''DNA droplets'' comprising designed DNA nanostructures.

Does DNA in the water tell us how many fish are there?
Researchers have developed a new non-invasive method to count individual fish by measuring the concentration of environmental DNA in the water, which could be applied for quantitative monitoring of aquatic ecosystems.

Zigzag DNA
How the cell organizes DNA into tightly packed chromosomes. Nature publication by Delft University of Technology and EMBL Heidelberg.

Scientists now know what DNA's chaperone looks like
Researchers have discovered the structure of the FACT protein -- a mysterious protein central to the functioning of DNA.

DNA is like everything else: it's not what you have, but how you use it
A new paradigm for reading out genetic information in DNA is described by Dr.

A new spin on DNA
For decades, researchers have chased ways to study biological machines.

From face to DNA: New method aims to improve match between DNA sample and face database
Predicting what someone's face looks like based on a DNA sample remains a hard nut to crack for science.

Read More: DNA News and DNA Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.