CRISPR-associated protein 1 (cas1) is one of the two universally conserved proteins found in the
CRISPR prokaryotic immune defense system. Cas1 is a metal-dependent DNA-specific endonuclease that produces double-stranded DNA fragments.
Cas1 forms a stable complex with the other universally conserved CRISPR-associated protein,
cas2
Cas2 is a protein associated with CRISPR that is involved with spacer acquisition. Representative cas2 proteins have been characterized as endonucleases that cleave single-stranded RNAs preferentially within U-rich regions, or as metal-dependen ...
, which is essential to spacer acquisition for CRISPR systems.
In July 2017, researchers led by
Jennifer Doudna
Jennifer Anne Doudna (; born February 19, 1964) is an American biochemist who has done pioneering work in CRISPR gene editing, and made other fundamental contributions in biochemistry and genetics. Doudna was one of the first women to share a ...
from the
University of California at Berkeley
The University of California, Berkeley (UC Berkeley, Berkeley, Cal, or California) is a public land-grant research university in Berkeley, California. Established in 1868 as the University of California, it is the state's first land-grant uni ...
, in
Berkeley, California
Berkeley ( ) is a city on the eastern shore of San Francisco Bay in northern Alameda County, California, United States. It is named after the 18th-century Irish bishop and philosopher George Berkeley. It borders the cities of Oakland and E ...
, using
electron microscopy and
X-ray crystallography
X-ray crystallography is the experimental science determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to diffract into many specific directions. By measuring the angles ...
, at the
Advanced Light Source
The Advanced Light Source (ALS) is a research facility at Lawrence Berkeley National Laboratory in Berkeley, California. One of the world's brightest sources of ultraviolet and soft x-ray light, the ALS is the first "third-generation" synchrotro ...
at
Lawrence Berkeley National Laboratory, the
Stanford Linear Accelerator Center, and the
HHMI
The Howard Hughes Medical Institute (HHMI) is an American non-profit medical research organization based in Chevy Chase, Maryland. It was founded in 1953 by Howard Hughes, an American business magnate, investor, record-setting pilot, engineer, fi ...
electron microscope facility at UC Berkeley, discovered how Cas1-Cas2, the proteins responsible for the ability of the
CRISPR immune system
CRISPR () (an acronym for clustered regularly interspaced short palindromic repeats) is a family of DNA sequences found in the genomes of prokaryote, prokaryotic organisms such as bacteria and archaea. These sequences are derived from DNA fragmen ...
(
CRISPR means: clustered regularly interspaced short
palindromic repeats
A palindrome is a word, number, phrase, or other sequence of symbols that reads the same backwards as forwards, such as the words ''madam'' or ''racecar'', the date and time ''11/11/11 11:11,'' and the sentence: "A man, a plan, a canal – Panam ...
) in
bacteria
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of prokaryotic microorganisms. Typically a few micrometr ...
to adapt to new
viral infections
A viral disease (or viral infection) occurs when an organism's body is invaded by pathogenic viruses, and infectious virus particles (virions) attach to and enter susceptible cells.
Structural Characteristics
Basic structural characteristics, ...
, identify the site in the genome where they insert
viral DNA
A DNA virus is a virus that has a genome made of deoxyribonucleic acid (DNA) that is replicated by a DNA polymerase. They can be divided between those that have two strands of DNA in their genome, called double-stranded DNA (dsDNA) viruses, and ...
so they can recognize it later and mount an attack. A protein called
IHF plays a crucial role in this process. Scientists also discovered that Cas-1 inhibits Cas-2/3 enzymatic activity as a nuclease and in the same discussion postulated that Cas1-Cas2 had an evolutionary origin as a toxin-antitoxin complex. This could result in a change in the evolutionary model of the Cas1-Cas2 complex.
References
Enzymes
{{enzyme-stub
