Crystal structure of archael chromatin clarified in new study

Mar 07, 2012

Researchers at the RIKEN SPring-8 Center in Harima, Japan, have clarified for the first time how chromatin in archaea, one of the three evolutionary branches of organisms in nature, binds to DNA. The results offer valuable clues into the evolution of chromatin structure in multi-cellular organisms and promise insights into how abnormalities in such structure can contribute to cancers and gene disorders.

Three distinct evolutionary branches of organisms make up all natural forms of life on the planet: bacteria, archaea and eukaryotes. Among these three, the domain known as archaea includes a variety of organisms that live in similar to those of an , thus offering arguably the greatest glimpse of what life may have looked like 4 billion years ago.

One area of great interest is the process by which DNA bind to proteins to compact and regulate the availability of , a process which is essential in all cellular organisms. In eukaryotes, proteins known as "histones" package and order DNA into a compact protein-DNA structure called chromatin. Archaea, in contrast, have no such universal chromatin proteins, instead using two or more DNA-binding proteins to package DNA. Alba is the most widespread and abundant such archaeal chromatin protein, present in the of every archaeal species that lives in high-temperature environments (thermophilic or hyperthermophilic).

While researchers know about the existence of Alba in archaea, the question of how these proteins bind to and compact DNA has remained a mystery. To answer this question, the researchers analyzed the of the Alba2-DNA complex from the archaea A. pernix K1 at atomic-level resolution using synchrotron radiation from the RIKEN SPring-8 facility in Harima, Japan. Their results indicate that unlike the chromatin structure of eukaryotes, Alba2 in archaea forms a hollow pipe with the duplex DNA running through it, with the hairpin structure of Alba2 stabilizing the pipe.

Published in the February 10th issue of the Journal of Biological Chemistry, this newly-discovered mechanism for compacting DNA marks a major step forward in our understanding of the evolution of chromatin structure. The results promise to clarify how abnormalities in chromatin structure can contribute to cancers and gene disorders, while also providing inspiration for the development of new types of biodevices.

Explore further: Four billion-year-old chemistry in cells today

add to favorites email to friend print save as pdf

Related Stories

Roles of DNA packaging protein revealed

Feb 12, 2009

Scientists at Albert Einstein College of Medicine of Yeshiva University have found that a class of chromatin proteins is crucial for maintaining the structure and function of chromosomes and the normal development ...

Elusive Z- DNA found on nucleosomes

Jan 20, 2012

New research published in BioMed Central's open access journal Cell & Bioscience is the first to show that left-handed Z-DNA, normally only found at sites where DNA is being copied, can also form on nucleosomes.

Putting the squeeze on sperm DNA

Sep 30, 2009

(PhysOrg.com) -- In the quest for speed, olympic swimmers shave themselves or squeeze into high-tech super-suits. In the body, sperm are the only cells that swim and, as speed is crucial to fertility, have ...

Researchers provide atomic view of a histone chaperone

Mar 01, 2012

Mayo Clinic researchers have gained insights into the function of a member of a family of specialized proteins called histone chaperones. Using nuclear magnetic resonance (NMR) spectroscopy and X-ray crystallography, they ...

Recommended for you

A new approach to creating organic zeolites

Jul 24, 2014

Yushan Yan, Distinguished Professor of Engineering at the University of Delaware, is known worldwide for using nanomaterials to solve problems in energy engineering, environmental sustainability and electronics.

User comments : 0