Original Assignee MedImmune LLC Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.) ( en Inventor Herren Wu Manuel Baca Jeffrey Swers Benoy Chacko Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.) Active Application number CA2704229A Other languages French ( fr) Google Patents Protein scaffolds comprising seven beta strand domains and six loop regionsĭownload PDF Info Publication number CA2704229C CA2704229C CA2704229A CA2704229A CA2704229C CA 2704229 C CA2704229 C CA 2704229C CA 2704229 A CA2704229 A CA 2704229A CA 2704229 A CA2704229 A CA 2704229A CA 2704229 C CA2704229 C CA 2704229C Authority CA Canada Prior art keywords randomized scaffolds scaffold invention comprise loop Prior art date Legal status (The legal status is an assumption and is not a legal conclusion. Google Patents CA2704229C - Protein scaffolds comprising seven beta strand domains and six loop regions This process is known as supercoiling.CA2704229C - Protein scaffolds comprising seven beta strand domains and six loop regions Instead of being wrapped around histone proteins the DNA of prokaryotic cells twists so much that the twists fold over onto themselves and eventually form a ball. Instead of forming ‘true’ chromosomes the DNA of prokaryotic cells coils up tightly into a condensed ball. In comparison, the eukaryotic cells of humans have 46 chromosomes which each stretch out to around 4 cm long. A prokaryotic cell has a single ring of DNA which stretches to around 1 cm long. Prokaryotic cells contain far less DNA than eukaryotic cells. Chromatids are replicated to form a chromosome.ĭNA + histones = nucleosomes (10 nm wide)Ģ x chromatid = chromosome Prokaryotic ‘chromosomes’ Loop domains continue to fold together to form a distinct structure known as a chromatid. Loop domains are around 300 nm wide, 10 times wider than chromatin. The next stage of packaging sees chromatin loop around a scaffold of proteins to form what are known as looped domains. Formation of chromosomesĭuring cell division, chromatin is packed tighter into chromosomes. The exceptions being when DNA is being replicated and transcribed. The looser packing of chromatin in between cell divisions makes it easier to access DNA for transcription.ĭNA is most commonly found packaged as chromatin. Sections of chromatin that contain active genes are positioned closer to the edge of the nucleus. Each chromatin fills a specific space in the nucleus of the cell. A fiber of chromatin is around 30 nm wide.Ĭhromatin fibers are packed into the nucleus of eukaryotic cells. The interactions lead to further folding and coiling of the DNA strand into a chromatin fiber. To form chromatin, a strand of DNA with nucleosomes interacts with additional histone proteins. As the DNA wraps around histone proteins small beads are formed along the DNA strand called nucleosomes. Firstly, a strand of DNA is wrapped around proteins called histones. In between cell divisions, DNA remains less densely packed in strands known as chromatin.Ĭhromatin is formed by the first two levels of coiling of DNA. ChromatinĭNA is not always packaged into chromosomes. In order for DNA to be packaged into chromosomes, several levels of coiling and wrapping is required. Eukaryotic cells typically have between 10-50 chromosomes. They are condensed structures that can easily be distinguished from one another and are found within the nucleus of eukaryotic cells. In order for all of this DNA to fit inside the nucleus of the cell it has to be packaged incredibly well.Ĭhromosomes form during cell division from strands of DNA and histone proteins. The length of the DNA packed into the 46 chromosomes of a bone marrow cell is around 46 000 times longer than the width of a cell. The width of human cells range between 10-120 µm. The full length of the DNA in one chromosome is around 4 cm (1.5 inches) long. Prokaryotic cells contain much less DNA which is packaged with proteins but not into ‘true’ chromosomes. True chromosomes are found only in eukaryotic cells. A chromosome is made from tightly packed strands of DNA and a huge number of proteins called histones. Chromosomes are genetic structures found in cells during cell division.
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